The development team behind Tony Hawk's Pro Skater on the GBA will be handling the Xbox port of Doom 3.
According to Eurogamer.net, Activision announced at its European Activate event that Vicarious Visions will be handling the Xbox port of Doom 3. Representatives from Activision were not able to confirm the announcement. Vicarious Visions is the development team behind the Tony Hawk's Pro Skater games for the GBA as well as the Xbox and GameCube ports of Jedi Knight II: Jedi Outcast.
News source: GameSpot