Microsoft Research has announced a new product, AutoCollage 2008, which enables you to take your favourite photos and build automatic collages.
You choose what photos to use, what size output you'd like (you could create a postcard, or PC wallpaper etc etc.) and then you just press the button and AutoCollage goes and builds the collage automatically.
You can find out more and download a free 30-day trial version of AutoCollage 2008 from the web site. A full version of AutoCollage costs GBP£19.90 and can be bought online.