A job posting by Bungie shows they are looking for a “Mobile Application Programmer” for their next project. While all signs have pointed to Bungie’s next game being a AAA, multiplatform title, the posting suggests that at least some element of the new game could be available on smart phones that support iOS, Android, and Windows Mobile.
“Our mobile development team is focused on establishing real time connectivity for millions of users and terabytes of data. Join our team and define the interface of Bungie’s next gaming universe to the world.”
Based on Halo, my guess is that it’s some sort of stats integration for multiplayer. And if Bungie.net is any indication, an app like that could be just as entertaining as the game itself.