Be sure to download the update to this program. If you run an older version on Tiger or later, the program will behave in strange ways! First it will generate a HUGE QuickTime file (what is supposed to be a 2.8 MB movie will become a 100 MB movie) and secondly, it will make your whole Mac run like it's in quicksand. If you think that Mac OSX can't crash you've got another think coming!
Properly updated, the program is easy to use and works nicely. Version 2.9.3 does have one bug that I've noticed: After zooming in the images, when you try to zoom back out, the images just scroll up, they don't zoom back out.
A tip if you want "longer" movies: Get QT Pro, and then turn on the "loop back and forth" feature when playing back your morph movie. Than the morph will play as long as you want!