I will post two guides, I used them both and they both work to root.
This method is from droidlife:
How to: Root DROID X Running Official Android 2.2
On 09.22.10, In News, Root (unlock), by Kellex
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Since so many of you are curious about having a rooted device, then you’ll be pleased to know that the
Droid 2 rooting method works flawlessly on the official update for the
Droid X. In even better news, the crew at
XDA Forums have created a semi-1-click method so that you no longer have to use a series of adb commands. You will still have to install the Android SDK, but that’s nothing right?
Instructions:
1.
Extract and Update Android SDK package to your computer. (Our instructions
here.)
2. Next, extract the files from the DORoot zip file to the tools folder of Android SDK.
(Take them out of the folder they came zipped in and place in tools.)
Ex: C:\android-sdk-windows\tools
3. Install Motorola Drivers: (
32-bit or
64-bit)
4. Enable USB Debugging on your phone and plug it into your PC. (Settings>Applications>Development)
5. Double-click and run doroot.bat
6. Let it run.
7. It will let you know if it has finished completely.
8. Reboot your phone and you are rooted!
If these instructions don’t seem all that clear, follow the step-by-step guide which includes adb commands. Our instructional post can be found
here.
Enjoy your newly rooted official 2.2 Droid X!
http://www.droidforums.net/forum/droid-2-hacks/80080-much-simpler-guide-rooting-no-pc-required.html