XNASharpNES is a NES Emulator for Xbox 360 using XNA. This is a Pre-Release because the authors need to finish a newer version that may support sound and even more games.

Done So Far:
* Basic Emulation (thanks XNAsharpNES)
* More roms Supported(thanks psp’s nesterj)
* Menu
* Main Menu Sound
* Layout
* Runs At 100%

To-Do:
* Option To Play with Keyboard Or X360 Gamepad
* Better Sounding Sound
* Port To Xbox 360 Using 2 Cpu’s Instead of 1
* Custimizeable Xbox360 Gamepad Controlls

http://allenthinks.com/nopxk9/xna.html