Brewology

1st: what FW are you using?

well i suggest downloading emulators from here (there pre-made to go on the psp, most u find on the web arnt)
and most the time there will be two folders like, __snes_yx% and __snes_yx, put both of those folders into ur GAME150 folder of ur psp.

Yea, you need a custom firmware first. Then you need to unzip that file. Then copy to the 2 folders to GAME150 like Akira said or you can copy them to the GAME folder. If you copy them to the GAME folder then you need to change the homebrew folder kernal to 1.50. To do so, just completely turn off the psp and turn it on while holding the R trig, and then to configuration and scroll down to bout the 3 item I think and it'll say homebrew folder kernal. Just change it to 1.50.

O and Akira is talking about the brewpack generator. I believe that is made to go into the GAME folder. And also when you use it you need to select firmware 1.50 even though you may have a custom firmware.