This guide is intended for the Droid 1 (Motorola Droid). If you have a Droid X, Droid 2, Devour, LG Ally, Samsung Fascinate, Droid/HTC Incredible, Droid/HTC Eris, or any other phone, I will do my best to answer your questions, but this guide will not be of any use to you past the tethering section. Please skip to the bottom to ask any questions you may have.
If you rooted via Easy Root, make sure you install Busybox before attempting anything else! See third post for reason why.
Also -- the SBF to install SPRecovery on 2.2 without having to flash your phone back to 2.0.1 or 2.1 is live! Thanks MotoCache1!
So you just finished rooting. Now what?
Well, in short, anything. You want to theme your Droid from scratch? There's an app for that! You want a total conversion ROM? There's an app for that! You want to overclock? There's an app for that! You want to tether? There's an app for that! Hell, there's two! Better backup tools? Got you covered! Total control of your Droid? Well, you got that now.
So... Now what?
Well, let's first start by asking, why on earth did you want to void your warranty and risk bricking your phone? Think about it for a minute.
I'll be here.
Still here.
Okay, you're with me now? Good! So, what did you decide?
1: Tethering.
This one's simple. Now that you're rooted you can do what Verizon refuses to give you -- WiFi tethering. Rooting your Droid is currently (and probably for ever more) the only way to get WifI tethering on your Droid. It's the main reason Verizon doesn't want you to root and it's the easiest thing in the world to accomplish once you've rooted. So, either download the apps from the market (available in free and donation flavors) and see which one works better for you or get it right from the source at Google's repository.
android-wifi-tether - Project Hosting on Google Code
If you're goals are a bit more basic, USB tethering (which has the added benefit of charging the battery at the same time), is available in almost every current custom ROM, but it's rather simplistic. If you want a feature-rich program that's clean, stable, and free, there's one on Google's repository.
android-wired-tether - Project Hosting on Google Code
Disclaimer: The following could potentially damage your phone. I, and DroidForums.net, make no warranty as to anything about the following information. It's for educational purposes only and if you do this you're acknowledging that you understand this warning and are doing anything at your own risk, etc. If the jargon is unfamiliar to you, you may find this post helpful.
http://www.droidforums.net/forum/hac...igy-lingo.html
Moving on:
You WILL have to flash in an alternate recovery image (SPRecovery or ClockworkMod Recovery) to install any kernel, complete theme, or ROM. This step is mandatory for the following procedures. The only exception is themeing with Metamorph, but if you want to do that you're on your own as I have no experience or desire to learn how to use the program myself. 
We now have a plain SBF file for flashing SPRecovery onto your phone safely under 2.2!
The instructions and file is located here:
Root Droid 1 - regardless of OS version
Thanks Motocache1 for making it and Christim for bringing it to my attention!
IMPORTANT!Make sure your battery is charged to at least 60%, preferably 70-80%, and/or plugged into a power source before attempting any flash. Even if it's plugged in, make sure the battery is at least 40%. Verizon recommends 20% when plugged in before flashing an OTA update, but at that point you are majorly risking the flash failing and/or a boot loop. Since you probably don't want that, please charge your phone for at least half an hour before continuing.
2: Overclocking, hopefully with less melting than Dali.
This one's a bit trickier. First you'll have to flash in a different kernel, then you'll have to install SetCPU from the market. It's a paid app, but well worth it. If you didn't root by flashing in SPRecovery, you'll need to either flash it in using RSDLite and the instructions here and the video here or you'll need to install ROM Manager from the market so you can get it to install ClockworkMOD Recovery. ROM Manager will prompt you to install ClockworkMOD Recovery and give you specific instruction on what to do next, as well giving you access to all the ROMs and kernels, etc., that devs have allowed to be posted within the app. Personally I prefer using SPRecovery because of the added control it gives me, but that's personal preference. If you rooted via Easy Root or DMUpdater, you may be more comfortable with ROM Manager. The only caveat to using ROM Manager is you might have to flash the recovery image a few times to make sure it works. Unfortunately ROM Manager doesn't seem to play well with FroYo at the moment, and it might turn out to be a liability to some users. Your mileage may vary, but be warned that even ROM Manager has some risks to using it. If at any time you find the instructions I'm giving don't gel with what you're reading in ROM Manager/ClockworkMOD Recovery, follow those instructions instead. And one last note -- a Nandroid Backup, or nandroid, is a snapshot of your system's current state; installed apps, homescreen setup, settings, etc. I believe ClockworkMOD Recovery calls them a Clockwork Recovery instead. While the name is different, they are essentially the same; just don't try to use one to restore your system in the other.
2a: Picking the kernel.
Picking the kernel is either incredibly simple or incredibly frustrating. It depends on your phone. Mine runs ChevyNo1's 1.2Ghz Ultra-Low Voltage kernel, but it gets too hot and will reboot if I run it that fast, so I pulled back to the 1.1Ghz ULV kernel. Some people will have phones that won't run reliably above 600Mhz, and some will be able to push it to 1.3/1.25Ghz. Voltage, minimum/maximum speeds all have to be considered. Also, if a kernel from one dev doesn't work, it's possible another at the same speed will. Every Droid is different. So is every kernel -- P3Droid has FroYo kernels that clock back to the original 125Mhz, for example. Figure out what you want before you try it; you'll be less frustrated that way. Some things to consider; Android 2.1 had issues running at 125Mhz, FroYo seems to have fixed this issue, but most Devs don't put 125Mhz in as a speed slot. The higher the voltage, the more juice is being sucked from your battery. Most importantly, the faster you're pushing your processor, the more juice you're sucking out of your battery as well. The net result is you have to decide which is more important -- battery life or clock speed. Using a lower-voltage kernel will help offset this a certain amount, but you risk lower stability as well. Choose wisely, my young padawan.
There are far, far more than just those two developers pushing out kernels, but you'll need to look for them yourself.
Make absolutely sure you're installing a kernel appropriate for your version of Android. Do NOT install a FroYo kernel in Eclair or vice versa. It simply will not work.
2c: Flashing the kernel (except in Texas where it's 1-3 for indecent exposure).
So you've decided what you want for a kernel and have it downloaded either to the phone via ROM Manager or have transferred it to your phone after downloading it onto your computer. ROM Manager will walk you through the next steps, so follow it very carefully, however, read 2b below before you flash the kernel in. If you're using SPRecovery you'll need to make sure it's saved as an update.zip (and double-check to make sure it's not a .zip.zip), then boot into recovery. Power your phone off, hold down the x key, and then power the phone back on while holding the x key until SPRecovery boots.
2b: Making a nandroid backup. (No, I did not mess this up, I have it set up this way for a reason.)
If you're using ROM Manager/ClockworkMOD Recovery, follow the instruction provided to make a nandroid backup post haste. I'm not kidding. Continue reading for why.
Now that you're in SPRecovery, you'll want to make a nandroid backup in case anything goes wrong with the flash and you get stuck in a bootloop or your performance goes to pot. How do you do that? Well, either using the D-pad on the keyboard or the volume buttons for navigation, go to "backup/restore", then either hit the center of the D-pad or the camera button to select it. Now navigate to "simple nandroid backup" and select it. Wait for it to finish and you've made a nandroid backup, possibly the most useful and best reason to have installed a custom recovery image in the first place.
2c revisited: Flashing the kernel part 2.
Okay, now that we have the backup made we can flash in the kernel. How do we do that? Well, ROM Manager/ClockworkMOD Recovery should talk you through that. If you're using SPRecovery, read on.
Back out of the backup/restore menu by either hitting the Del key on the keyboard or the power button until you're on the main menu. Move down to "install" and select it. Now move to "allow update.zip" and select it. Make sure you've done this or the install will fail. Go to "install update.zip (deprecated)" and select it. Your install will begin immediately. Once it's done, back out to the main menu and select reboot. Your phone should boot to the desktop. If it does, congratulations, you now have a different kernel! If you get stuck in a boot loop, pull the battery, reboot into recovery, and restore that nandroid backup.
Now, aren't you really glad you made it?
If you had to restore your nandroid backup, don't despair, merely try another kernel. Try lowering the maximum speed, or move to a higher-voltage kernel if you tried a low- or ultra-low-voltage kernel. If none of the kernels by that Dev work, try another. You should find one that works eventually.
A video on installing update.zip files in SPRecovery can be found here. It's geared towards ROMs, but the procedure (other than the wiping, which you shouldn't have to do just to flash in a kernel this early in the game), is outlined in this video.
Video: Installing a Custom ROM Using SPRecovery | Droid Life: A Droid Community Blog
Be sure if you are now installing SPRecovery on a stock 2.2 phone you use the SBF from this link!
http://bit.ly/RO_SPR_SBF
DO NOT WIPE FOR A KERNEL FLASH OVER A STOCK KERNEL. You will lose all your settings and data and have to set your phone back up again.
2d: SetCPU.
Download from the market, install, and run. It talks you through the procedure. Setting up the profiles is up to you, but you should have an overheating profile at the bare minimum, as far as I'm concerned, and one that clocks the phone down when the screen is off. The reasons for this are simple -- if the phone isn't in use, why have it running full-bore, and if the phone is overheating, why risk physically damaging it by running it at maximum speed? It's up to you, but that's some friendly advice.
Experiment to find out what works for you. If you need more advanced settings, read http://www.droidforums.net/forum/hac...ing-101-a.html and pay attention to which version of Android Skull One is referring to -- the settings for FroYo are different from Eclair. Don't get them confused.
Congratulations, you're now running an overclocked Droid. Just keep an eye over the next few days on the heat and the battery life to see if what you're running is good. Otherwise you'll need to change settings and possibly flash in another kernel. Remember to make your nandroid backup!
On that note, I'm heading off here because it's pretty late. I'll update this post as soon as my schedule allows. I hope this was helpful!