I have been using a trial version of Lumapix FotoFusion for a while and whilst I was (on the whole) impressed it's quite an expensive piece of software. I use the software to set up mug templates etc. and find it really useful.
They used to have different versions starting but now the cheapest is $119. I guess it would be worth it but I thought I'd look at alternatives anyway.
So, I had a search around all the free offerings, nothing too exciting there. Downloaded a few trials for 'paid' software and came across Picture Collage Maker Pro. This retails at $39 so quite a bit cheaper. Not quite as slick as FotoFusion maybe but certainly has all the features I was using before and to be honest seems to be running better as well.
Very useful software and worth a look. Yes, I know you can do this in Illustrator, CorelDraw etc. but this program does simplify things a great deal.