Panoweaver is a professional tool that will take multiple digital photos covering different areas of the same scene, and stitch them together to produce full 360 degree or partial panoramas in many different formats.
At its simplest, the program is entirely automatic. Create a new project, point Panoweaver at your images, click Stitch and it will go to work, checking for matching areas between the photos. It just a few seconds they'll all be stitched together in the appropriate places, and you'll be looking at a full panorama based on your images. (This trial version adds watermarks all across the finished panorama, but of course that won't be present if you buy a licence.)
If necessary, though, you can also customise the output in various ways, perhaps tweaking the resolution of the output image to best suit your needs.
And when you're happy Panoweaver can publish your panorama in a variety of formats: HTML-based Flash VR, QuickTime movie (*.mov), standalone .swf, and Easypano's own virtual tour player (requires Java).