A7800DS2 by alekmaul is an Atari 7800 emulator for Nintendo DS to be used with a Supercard DSTwo flashcard. The emulator tiself is based upon Prosystem. The difference between the DS (not DSi) version is, that this DS2 version is full speed but the sound is not good.

A7800DS V1.0
Watch this video on YouTube.

http://gbatemp.net/t294179-a7800ds2-emulator-dstwo-entry