Adding Photosynth and Floor Plans to Bing Maps
Hannes' Virtual Earth Blog has a good tutorial explaining how you can create a Bing Maps mashup with Photosynth and floorplans of buildings.
The tutorial explains how you can create your own map tiles from a floorplan and integrate your floorplan with Bing Maps. To add a little fun interactivity the tutorial also explains how you can embed Photosynth images into your floorplan map.
Demo one - Microsoft Campus
Demo two - Art Gallery of New South Wales