Google Labs adds another feature to its collection.

This one is known as Google Image Swirl:

Search: Statue of Liberty

Click on the link and type in a familiar image.  The results will look like the regular thumbnails in Image Search but will appear to be stacked.  When clicking on the front image, it will then expand into circles with similar images.

Google says that Image Swirl works with about 200,000 images currently.  It will auto-complete the image name in the Search box if it is available in Swirl.  They plan to expand the number of images with which you can use Swirl.

-source: Chris Sherman, SearchEngineLand.com