This one is just cool:

What is AutoCollage?

Photo collages celebrate important events and themes in our lives. Pick a folder, press a button, and in a few minutes AutoCollage presents you with a unique memento to print or email to your family and friends.

Try it now!

Download AutoCollage 2008 now and start creating your own collages within minutes.

Maximize your photo collection

AutoCollage allows you to create beautiful collages of your favorite pictures in a few clicks of a mouse. See the program in action, or meet the team behind it.

 

Apparently you have to pay for it ($19.95 in the US), but there's a free trial as well.