Microsoft announced at E3 2008 that a South Park game was coming to Xbox Live Arcade. We couldn't find it at E3 2009, but we did get an update.
"South Park actually is coming," John Schappert, Microsoft's corporate vice president of interactive entertainment LIVE, software and services said in an interview with Kotaku yesterday. "I think what you saw in our [Xbox 360 press] briefing is that there was so much rapid-fire information that we just didn't have time to cover everything."
Schappert said the game is still a Live Arcade game, that it's "a lot of fun and looks great." It will be out this year, he added, but declined to provide any gameplay details.
The game has been in development at Doublesix and has been listed on Xbox.com as a strategy game.