The Android platform may soon get a sizable shot of retro gaming, if Jrioni's GP2X emulator project continues to develop. Currently in "pre-alpha" stage, the project basically recreates the GP2X open-source Linux-based handheld on an Android phone like the T-Mobile G1.
Since the GP2X is capable of playing classic titles from the Neo Geo, Sega Genesis, Master System, Game Gear and Commodore 64, among others, that means there's a huge back-catalog of potential games. In this demo video, Jrioni plays Marvel vs Capcom and Samurai Shodown, among others.
No word on when - or even if - we can see a release of the emulator, but there undoubtedly seems to be demand for it. Another of Jrioni's projects is streaming video to the G1 via VLC and vnc.