I don’t have a PSP, and i’ve only used one once for 5 minutes, so i really can’t say much for how well the controls work, but this looks like an awesome modding job if i do say so myself.
F00 f00 over at Acidmods.com hacked his PSP to connect a Dual shock controller from a PS2 up to it. And, he says that SNES controllers are in the works. Very nice. Video of it in action after the click: