I purchased a psp slim today and it has firmware 4.05, what do I need to do to get it to run homebrew and (legal) roms?

I would like to put my new PSP Slim to full use by doing things that you cant normally do. (ie: play FF7 [or any PS1 game], SNES (legal) roms, “skin” the UI to make it look like mac OSX, etc.)