Check it out here :
I don't know how effectively the controls would work with the clickwheel and all, but if you're one of the daring hackers out there who has installed Linux on your iPod and you're a gamer to boot, you'll be glad to hear that some crazy maniac out there is working on a Gameboy Emulator for the iPod. This doesn't look to be any sort of hoax, as there are some pretty convincing videos available of different games like Legend of Zelda and Mario running on an iPod with a color screen (albeit running very slowly).
You have to read through a lot of the forum to find the bits that aren't "when is the going to be released?" and "h00t!", but it looks like they have Mario running close to full speed ... on an iPod ... which is insane.