the lists of emulators are nice, but sadly I found out the hard way that there are very few platforms the DS can
actually emulate at full or even playable speed.
So far Gameboy, Gameboy color (for the most part), Atari 8 bit (terrible sound and slightly slow but playable), C64 (some games dont work and some are a little slow but overall good), and NES.
Everything else I've found to be disappointing. I would appreciate if anyone can add to this list with their experience. I mean who cares if the DS can emulate a SNES or Atari ST if it can only do it at 10% speed?