Try The Rasterbator
Try The Rasterbator | GeekSugar
This is a cool find from the GeekSugar blog, The Rasterbator.
“The Rasterbator is a brilliant application that creates huge, rasterized images from any picture. All you have to do is upload an image, print the resulting multi-page pdf file and assemble the pages into a beautiful (or disturbing – it all depends on your original image choice) poster”
There is also a cool gallery of rasterbatorized images. (link)