NES.app uses the popular InfoNES emulation core to mimic the 6502 processor in a Nintendo Entertainment System, allowing you to play ROM dumps of games designed for the NES console. ROM dumps are files containing the dumped instruction code from a physical cartridge.

Changes since v0.53:

[nervegas] Implemented game genie code support (but slows down game)
[nervegas] Fix for preferences scroll speed (cell scope problem)

http://iphone.natetrue.com/nesapp/