Jonz has released a new version of his Nes Emulator for the iPhone:

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.

In order to use NES.app, you will need ROM images of Nintendo games. ROM images are files containing the dumped instruction code from a physical cartridge. In many cases, you are legally entitled to posess a ROM imageof 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.

Features
Multitouch: Use the directional pad + A + B, or other combinations
Landscape Mode: Turn the iPhone counter-clockwise to play in landscape mode
Zapper Tap: Tap objects on the screen to shoot them
Full Screen: Enlarge your NES picture to the max possible
Save State: Save an instant snapshot of your game and come back to it later
Game Genie: Use Game Genie cheat codes
... and many more
NES.app is not iPhoneNES!
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.

2.3.1 [jonz] Added setMagnificationFilter [OFF] thanks stroughtonsmith

Latest binary release [ 7/27/2008 ] for iPhoneOS v2.0