Playing roms on the Nintendo DS?

[Mockery]

I've heard about flash drives 'n stuff for the GBA and I know the DS supports GBA games... so my question is, is there a good package that I could get to run various emulators on my Nintendo DS? It'd be cool to be able to play a bunch of old out of print Sega Genesis titles 'n what not on the Nintendo DS in addition to the games I buy for it.

[EverythingWillSuck]

I read that you could play GBA flash cards on the DS.