PhotoSynth lets you take loads of pictures of the scene that you are trying to capture and simply load it up in the desktop software. This software then looks through all the pictures and finds overlapping areas and then stitches them up automatically. Then the newly created picture could be uploaded to the PhotoSynth servers for viewing.
Read more and see it in action here:
http://photosynth.net/about.aspx
http://blogs.msdn.com/photosynth/archive/2008/08/20/welcome-to-photosynth.aspx