Danny Sullivan blogged about a Search Engine Watch thread named Google Earth on an interactive tabletop display, Minority Report style!
The thread links to a video at Google Video named Google Earth on a Table. The video shows how a PhD student put a layer over Google Earth to make Google Earth work a lot like how the Minority Report movie's interactive technology worked. I.e. with voice commands and touching screens seamlessly.
If you got some time, check out the video at Google Video.
Forum discussion at Search Engine Watch Forums.