YUI - Image Cropper

Yahoo has several JavaScript user interface controls that are free to download and use in your site.  I found a new one this morning called Image Cropper.  I haven't had a chance to play with it much, but it looks like it overlays an images with a crop box similar to Photoshop so you can enlarge and shrink the crop. 

http://developer.yahoo.com/yui/imagecropper/

And examples at http://developer.yahoo.com/yui/examples/imagecropper/index.html

Now I've just got to figure out something cool to do with it