FYI, this image is by far my most-stolen photograph. First some guy who goes by TheFrogman stole it and put his *own* copyright message on my photo, adding some caption text on it (for those who don't recognize the humor inherent in the photos and need it spelled out for them, I guess). His "copyrighted" image has appeared many places, and others have taken it and added *their* branding as well. I've even seen this photo for sale on a poster site - how sweet, I could buy a copy of my own photo if I wanted to.
Thanks to Paul (below), my friend George and others I now know what to do about these rip-offs: file a DMCA Takedown Notice. It's simple, it's fast, and it works! I've managed to have other people's "copyrighted" versions of my photo removed from many sites. If somebody has ripped off one of your photos and put their own copyright notice on it, follow the links Paul provided below to have it removed from sites.
My general rule of thumb is that I don't do anything about unattributed use of my photos except to try to get them to link to the original, but when people start labeling my photos as "their property" it's time to get lawyers and government agencies involved. In my experience, reputable web sites are quick to respond if you file the proper paperwork about such theft.