Ethos has posted news on his site of his port of a Gameboy/Gameboy Colour emulator to the Nintendo DS Console, heres the news first:
Got some nice progress on my emulator, but when I started implementing GBC I realized I needed better optimization. Here are the screens before I totally overhaul my emulator. GB is playing at good speed and GBC at slow ass speed. lol, learning ARM assembler + registers is looking more appealing day by day.