If you've got photoshop, it's got a built in panorama maker. (File -> Automate -> Photomerge). Some cameras come with pano software on a CD as well.
The best pano software is probably PTGUI but it's quite expensive for a personal edition (£70) but they do a trial version which watermarks the images. It supports RAW as well. From my experience it does the best job of stitching and getting colouring right, I made quite a few panos successfuly from hand held shots.