Hit the MacRumors link below to see a mind blowing conceptual video. Also Engadget has some dirt on the history beyond the Courier concept. I'm not going to lie, this video just set my expectations for Apple's Tablet very high.
Microsoft's Prototype Multi-Touch Tablet/Booklet: "Gizmodo reveals some details about a top secret Microsoft project working to introduce a new booklet device with dual 7-inch multi-touch screens. The dual 7-inch (or so) screens are multitouch, and designed for writing, flic..."