Kinect adopters won't be limited to spending face time with just each other come launch, as Marc Whitten, Xbox Live general manager, has confirmed the sensor will interact with Windows Live Messenger on PCs. "I'm also excited to confirm that Video Kinect will integrate with Windows Live Messenger at launch, so Xbox Live members can video chat with hundreds of millions of PC users around the world," he said in a press announcement.
However, it appears the cross-platform functionality will be limited to video chat. If you were hoping to invite your PC pals to virtually watch Harry Potter and the Goblet Devils of Shamshire (or whatever) with you, it's not happening. As if they'd stop playing StarCraft 2 long enough to join you, anyway.