NES.app v1.2.1

via pdroms:

NES.app is a Nintendo emulator for Apple's iPhone. NES.app uses a modified version of 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. In many cases, you are legally entitled to posess a ROM dump of any game that you presently own. ROM images for NES are widely available online, or with the appropriate hardware, you can dump them yourself directly from the cartridge.

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 full sound, game genie codes, saved games, battery-saved ram support, and full screen support.

Changes since v1.2.0:
*Fixed scanline processing
*Should notice improvement in speed and sound sync

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

Man this got picked up a few days after being mentioned in irc I see, by the way 1.3.1 is out now:
1.3.0 [nervegas] Forked InfoNES/pNESx to separate NESCore project
Fixed scrolling and nametable issues - many games that
previously had problems now render properly, or mostly:
Rad Racer, SMB3, Zelda, Zelda 2, Megaman 3 and 6,
Toki (Game Screen), RC Pro-Am (Dashboard), Rolling
Thunder, GI Joe, others.
New core: http://iphone.natetrue.com/nescore/
1.3.1 [nervegas] Applied patch submitted by Jordan Laughlin:
Switch to CPU timing instead of PPU timing
Cleaned up scrolling code
Kung Fu and others render properly now