This looks like a great idea. I was wondering how to work easily in SketchUp on a Tablet PC. The main drawback was always the lack of a wheel-mouse.
This might be great for community charrettes where the actual model gets modified during discussions.
Get the how-to on this forum page: Sketchup & tablet pc: gestures! (via SCF). The software used is called StrokeIt. Another option is gMote.