Hit the video at about minute mark 3:00 to get the video-intensive scoop. Here's the text-version: the idea is that you can set multiple Windows Mobile devices next to each other and they'll begin to share resources. So you could span a movie across multiple screens, set the devices about the room for true surround sound, share processing power for heavy tasks, share battery power (via a wire, of course), share radio connections, and so on. Basically Microsoft wants to be able to aggregate the any resource on any Windows Mobile phone when they're in proximity to each other.
We're talking future-science, here, as it's just a patent application for now. Yet it's nice to know that Microsoft is thinking big about mobile.