Well, if the end result is that you want to hack a PSP game, maybe starting with a PS1 game is more appropriate, but I really couldn't tell you. IIRC, the PS1 isn't as well documented as, say, the NES. But like I said, I'm not too knowledgeable with it myself. See if you can find Gemini, s/he's done a few PS1 translations/hacks. Dunno who else could help you. Maybe post in the Newbie forum (don't worry, it just means you're willing to learn and I've seen people be helpful in that thread)?