http://www.zodttd.com/boards/index.php?showtopic=7130
This guy is legit fyi. He is the guy behind most any emulator you will run into on the iPhone OS. Currently he has a build working for the 3GS. Yes I know it is not jailbroken yet but non the less it is working. I paid him his 10$ and now I can run PSX games on my iPhone with a good deal of success. Zod generally will only charge for access to his betas and the final versions are free to use.
Just so you know he changes the carrier provisioning to get the Emulators on the device and working. This will not in any way affect any normal user but it has undone my tethering/mms hack. Now I have to decide on PSX emulation or tethering! Haha trying to find a way to get both rolling atm.