ok im not sure if this gets asked a lot, but im a total noob when it comes to emulators on the ds. currently i have a psp and am thinking about switching over to the ds. how hard is it to get emulators up and running for the ds? what kind of emulators are out there, nes, snes, gb, gba? what kind of hardware/software will i need to get them running, and about how much does it usually cost(im in the US). finally, is it possible to get mp3s on a ds? thanks a ton in advance.