Are you a 1.5 or OE firmware user?... if not homebrew is useless to you, but anyway I suggest googling
Emulators:
Daedalus PSP ( Nintendo 64)
Gpsp( gameboy advanced)
Dgen 1.7 ( sega genesis)
G.e.m.p. ( Gameboy/ gameboy color)
Snes TYL ( Super Nintendo)
Nester J ( nintendo)
MMSPlus ( sega master system)
Games:
Super Mario War
KETM ( kill everything that moves)
Attack of the Mutants
Doom PSP
Trigonometry Wars
48 Hour Pong
PSP Revolution
Bookmarks