Microsoft Director of Programming for Xbox Live, Larry Hryb (AKA Major Nelson) announced that:

Xbox Companion for Windows Phone coming December 6th

The free app for Windows phone will provide the following features:

• Xbox Companion search powered by Bing
• Search the unified Xbox catalog for movies, TV shows, music, games and apps using the Windows phone
• View a detailed unified results page across all content providers.
• See recently played games and apps and browse the Zune video catalog