Microsoft Research makes their Image Composite Editor available for free. Use the ICE to create high quality panorama photos by stitching together many photos.
This photo was created out of 34 photos taken on a 12 megapixel point n shoot camera – the end result, after overlaps and cropping, is a 78 megapixel image.
This is a size reduced 1920 pixel wide version of the original. On the original, I can just about zoom in to cars on the bridge. This photo was taken from the site of the Astoria tower, Astoria, Oregon, overlooking the Columbia River where it joins the Pacific Ocean.