I ditto metatransitions suggestion of using Piccassa. Its a great and easy way of messing around with colleges while it lets you add boarders to some/all the images and has a choice of different layout selections.
I used Picasa for the two from Wednesday and Thursday and it didn't save the info... could it be because I uploaded the finished product to Picnik first? Even though Picnik keeps it too? GAH I JUST DON'T KNOW D:
http://www.makeuseof.com/dir/hockneyizer-photo-collage-generator/
try also big huge lab of flickr...
bighugelabs.com/
have fun =)