NES.app lets you play Nintendo games on your iPhone. It is a fully functional, feature-rich Nintendo emulator.

NES.app uses an emulator core we call NESCore, which we’ve forked from pNESx and InfoNES and re-engineered as a highly-portable and high-performance Nintendo emulator core.

NES.app started as a fork of iPhoneNES v0.01, but has been completely rewritten to run very fast, and with many additional features including sound, multitouch support, full-screen, landscape mode, game genie codes, saved games and much more. It now contains zero code from the original iPhoneNES project.

Changes:

[nervegas] Fixed navbar so buttons update when in landscape mode
[nervegas] Use fclose() instead of close() in LoadROM
[nervegas] Added “Sensory Pad” preference option, good for RPGs I guess
[nervegas] Cleaned up controller selection code and filenames
[nervegas] Enlarged “A & B” hot spot in portrait mode
[nervegas] Tweaked color palette for optimal display on iPhone
[nervegas] Stabilized frame skip, less jerkiness, fewer changes
[nervegas] Added color palette preferences option (old palette = C)
[jordan] Optimized scanline rendering routine

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