From what I understand, the nintendo systems are all universally compatible. The portables don't require any kind of internal swapping, or my GBA doesn't. I don't think that the eletronics to one would be any different either, except the actual charger would be a different size for the plug. Everything else should be the same, though.

The shit they're talking about doing on the DS is unreal, though. There's an espionage game in the works where the bottom screen changes about 3249723968237 times in the game, from doing stuff like typing #s in a keypad to open a door to typical map stuff and weapons changes and such. They're going crazy with it on a lot of games, though... I'd be interested in seeing a Monkey Ball done on it, bet that'd be bad ass.