I have sprecovery and nandroid backup done, what do I do next to change roms and overclock?
You will want to read up on some ROMs... Some good ones such as UltimateDroid v10 are available as SP Recovery Nandroid restores, others are available as update.zip's which you apply in SP Recovery or Clockwork... Also you might want to look into buying the full version of ROM Manager as many of them are easily downloadable and installable using that APP.
As for overclocking, you will need to buy SetCPU on the market and make sure you have installed a kernel to the speed you desire...
I know this is blah blah, and been asked 1upteenth time, but there are so many sections on rooting. How do I know which one to use. My phone is 2.1 and I have no clue how to root because it says to rename the zip file????? Then put on sd card, I have no clue how to do that either. Should I just give up?