Seen as though were allowed to post links, if not sorry im just following
nelsonpks post.
I hacked my PSP to CFW 3.71 M33 i think. works great, downloaded a crap load of games and all working flawlessly.
Anyway, a complete guide on how to hack your PSP is here.
EDIT: Removed, Didnt see nelsonpk was BANNED lol...