Not to condone piracy or anything, but there are a plethora of SNES emulators available on the Nintendo DS. Some of these (such as snesDS or SNEmulDS) do have fully working games that run on the DS.
The real problem here is that most of these emulators have stop being updated so compatibility issues aren't being resolved.
slugo writes: The house that Sonic built is getting significantly smaller.
Sega's Japanese main branch said Tuesday that it will close 110 arcades, cancel some games in development and seek to lay off 18 percent of its staff.