First we had NES, then we had GBA, now we have PS1 emulation on the iPhone and iPod touch. Opening up the iPhone to PS1 really shows the iPhone's gaming capabilities. While still needed to be optimized to run faster, I guess you could play a game. It's only about 10-15FPS right now, but as we saw from the other emulators, after time we eventually obtained playable FPS rates on most games.  

Right now the emulator is slow and games are barely playable. We can hope within the next couple of updates we can increase the FPS and get a playable game. PSX emulator can be obtained in installer.app.