NerveGas, the developer who forked "StepWhite"'s iPhoneNES program from StepWhite's proof-of-concept version 0.01 to actual playable product, has announced Released Candidate 1 for his NES emulator.
The emulator, which uses a modified version of the InfoNES emulation core, is a separate development effort and should not be confused with the original Google Code iPhoneNES project. StepWhite's original code has been removed from NES.app and replaced.
NES.app includes Game Genie, saved games, sound, and battery ram support. It provides both landscape and portrait gameplay and uses multitouch to allow you to access more than one game control at a time.
NerveGas has released his code under the GPL. Since NES.app uses the iPhone's proprietary APIs, you may want to scope out the code to pick up some iPhone programming tricks.