Create panoramic images, even HDR, with Hugin
Hugin is a free graphical user interface for Panorama tools.
Panorama Tools is a set of free programs and libraries, decicated to re-projecting and blending multiple images into a panorama.
Hugin can correct exposure, vignetting and white balance, that may differ from photo to photo.
hugin can also make HDR images or give an exposure blended output from bracketed photos. It will also let you use 16bit and HDR images to create a panorama.