I'd suggest this:
iClarified - iPhone - How to Select an iPhone Unlock/Jailbreak Tutorial
There you can find a tutorial about each case! It depends on what OS you're using... iPhone type, FW, etc... Select your's and go through with it. You'll do better with 2.2 I'm sure!
Please remember to be in 10.5.6 MAC OS X and 8.0.2 iTunes. Otherwise if using Windows just check! Then just prepare everything and complete the process!
I've done it several times with MAC OS and until now got 0 Errors!
Cheers,
N