Peggle is a ridiculously popular pachinko-esque puzzle game about bouncing balls around on pegs. It's so well-regarded that it made Joystiq's Top 10 of 2007. A version was also included in The Orange Box for PC, which makes it "okay" for professed hardcore gamers to enjoy it.
PopCap's John Vechey told Pocket Gamer that after the game's Xbox Live Arcade port is released, a DS version would be on the way. He didn't give any details about the release other than that there would be one, and we don't know when or for what region it's coming out.