Wikipedia
PTGui
PTGui is a panorama photo stitching program for Windows and Mac OS X developed by New House Internet Services BV. PTGui was created as a GUI frontend to Helmut Dersch's Panorama Tools. It features its own stitching and blending engine along with compatibility to Panorama Tools. PTGui supports telephoto, normal, wide angle and fisheye lenses to create partial cylindrical up to full spherical panoramas.
The 'free trial version' of PTGui is fully functional but creates panoramas with embedded visible watermarks.
PTGui pro also includes HDR and tone mapping support.