Probably the most eye-opening site I've ever used, thought it may be of interest to some people...
http://www.tineye.com
Basically, upload or link to one of your images and it will scan the web for usage of it. The first one I tried of mine came back with 64 hits (all of which were genuinely my photo), a few people passing it off as their own on Flickr, more so on DeviantArt, lots of Wallpaper sites, even today.com (big MSNBC website)...then as a bloody album cover!
http://www.tineye.com
Basically, upload or link to one of your images and it will scan the web for usage of it. The first one I tried of mine came back with 64 hits (all of which were genuinely my photo), a few people passing it off as their own on Flickr, more so on DeviantArt, lots of Wallpaper sites, even today.com (big MSNBC website)...then as a bloody album cover!