Alex Lindsay's pick on MacBreak Weekly episode 393 is PTgui. This is a full featured Mac and PC application for stitching any number of photos together seamlessly. PTgui stands for "Graphical User Interface for Panorama Tools," and started out as an app that ran from the command line. This is different from a lot of photo stitching apps because it gives you more manual control of the process.
PTgui can stitch multiple rows of images and create 360 degree cylindrical panoramas. It even can do a spherical 360x180 degree image. It has a virtually unlimited output size, and is capable of stitching hundreds of photos together. Alex says this is geared toward people who are really serious about photo stitching. If you're only doing this on occasion, then Photoshop would probably be sufficient.
There are personal and professional versions of PTgui available. The regular license is $113, and the professional license costs $213. There are also company licenses available: $257 for the standard version, and $498 for the pro version. There is a free trial available as well.
To hear more from Alex Lindsay about PTgui, check out MacBreak Weekly episode 393.