Dead Rising 2: Case West was announced by Capcom at TGS today. It's an Xbox 360 download.
According to the company the game, "will extend the Dead Rising 2 experience by delivering brand new content and the return of a familiar face... (it) will see Frank West team up with Chuck Greene for some serious co-op action. In co-op mode, Xbox LIVE Gold members will see the two protagonists delve deeper into the reasons behind the Fortune City outbreak and provide further links to the Willamette incident."
Watch the video, view the shots...