Microsoft Research Image Composite Editor (ICE)
Microsoft Image Composite Editor (ICE) is an advanced panoramic image stitcher. You shoot a set of overlapping photographs of a scene from a single location, and Image Composite Editor creates a high-resolution panorama incorporating all your images at full resolution. Then save your stitched panorama in a wide variety of formats, from common formats like JPEG and TIFF to multi-resolution tiled formats like HD View (do read about the HD View process) and Silverlight Deep Zoom. Can also read this article for a quick overview of ICE.