Autostitch From their website: AutoStitch is the world's first fully automatic 2D image stitcher. Capable of stitching full view panoramas without any user input whatsoever, AutoStitch is a breakthrough technology for panoramic photography, VR and visualisation applications.
AutoStitch is built using cutting edge research from the AI lab at UBC, but it's incredibly simple to use! Just select a set of photos, and AutoStitch does the rest: digital photos in, panoramas out.
Currently the developers distribute this from their website as a fully functional demo. It's really an amazing product! I created a pano from 36 images I shot while skiing (no tripod) - the end result was perfect. I have stitched 3 shots, 15 shots, 36 and everything inbetween - all with near perfect results. Keep in mind I did not use a tripod for any of these, so some errors were pretty much a given. The product was not designed for 360 panos, and the widest I have created is 270 degrees. Stitch time is pretty quick. When you're assembling your pano software, this is a must have! You can see some of the results at Add360.com - Ski Area Tour
A complete panorama stitching suite based on that same technology is Autopano pro