This is this link for XDA unlocking, rooting, and installing recovery for the Nexus S 4G. I used this with build GRJ22. I take no credit for this. I just wanted to share here on PPCGEEKS.
[GUIDE] Step by Step ROOT Nexus S via ClockworkMod Recovery image (i9020T only) - xda-developers
If you have any problems you can read that forum or I will try my best to help.