I found this cool little program today... it combines photos together that are overlapping at the sides.
http://www.cs.ubc.ca/~mbrown/autostitch/autostitch.html So far I'm pretty happy with what it can do! It combined these three photos to this panoramic in about 5 seconds!
My photos of the extinct crater of the Masaya Volcano in Nicaragua.
into this panoramic
and with some cropping: