Some people have also been successful with z4root to gain temporary root, then get superuser from the market. Then use rom manager to flash clockwork. Then you can flash s-off.
After you flash clockwork with rom manager you will be able to boot into that recovery and flash the s-off file(unrevoked forever) available on unrevoked's site.
so i tried this and yes,it was that easy.
i unrooted my phone,and checked for software updates,just to make sure.
i then moved the z4root app,and the superuser app that i linked above to the sd card.
-i ran z4root and obtained temporary root. (superuser app appeared automagically,i didnt have to download it)
-i downloaded rom manager from the market.
-i made sure "erase recovery" was checked in rom manager settings,then cleared download cache
-i flashed clockwork recovery and booted into it. at this point,you could do alot of things:1) you could flash the superuser app i linked if you wished to continue on a rooted stock rom. 2) you could also flash the custom rom of your choice. 3) i guess you could also do nothing,if you dont care about being rooted

wichever of those things you do,you definately
should flash unrevokeds forever tool(im allready s-off,so i didnt.otherwise i would have to make sure it works.if you really want me to,ill turn s-on and redo the whole process)
what i did was reboot to make sure temp root was gone... it was. rom manager wouldnt let me boot back to recovery,and set cpu couldnt get root access. superuser app was still there,but not doing anything. so i powerd off,powered on into hboot(power+volume down),selected recovery and there was clockwork 3.0.0.8. this time i flashed the SU app and rebooted. root access restored. yay! rebooted one more time to make sure it "stuck"
so to the OP,if you havent done this allready,quit stressing out about unrevoked and just do this. its maybe not the typical method,but it worked.
now im flashing Amons recovery back so i can restore my cm7 backup.
