I don't know if this thread will be that helpful, and also a lot of you probably know about this. But zodttd, has actually gotten a PS1 emu working on the iPod touch.
ZodTTD: Home Of Homebrew Videogames
"My very first build of psx4all for the iPhone & iTouch worked! You gotta love when the first compile for a program works!
These are two quick screenshots of the very first build (note: not a release, just a work in progress) ...
These images won't reflect how the release will look. Also ignore the data in the debug information at the top, as it's not accurate.
What can you look forward to in the first release of psx4iphone? Depends on how the beta testing goes. I will be working on the existing dynarec (cpu emulation) quite a lot to improve performance as it will be required. The screen scaling and screen placement will be drastically improved over the above images. Memory card support will work, and save states might work. Sound will be implemented as well. The interface/gui will be very similar to gpSPhone's just with 4 hard buttons instead of just A+B, and L2 and R2 buttons. A rough estimate would be about 75% of games will be compatible. With such a large library of games, this may or may not include your favorite game. Performance will have to be increased about 25% to get a good portion of games running smoothly. This can be done.
I will be contacting those who donated to me (for gpSPhone and psx4iphone) when a beta of psx4iphone (also works on iPod Touch) is available. If there's a large amount of beta testers and the demand is there, it could be within a matter of days.
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PS:/EDIT: Mods, you might need to make another sub forum for this emulator. When a public release comes out. =D