Remember a couple of years back when a Reuters photographer got busted for manipulating photographs in Iraq to make them more, er, interesting? More smoke and whatnot. Well a guy, John Graham has written C code to detect Photoshopped cloning in images. He basically did it because he wanted to win a car in a Spot The Ball newspaper competition, and found a paper describing the algorithm he was looking for. He didn't end up winning the car but the program seems to work quite well. (See the images below).
You can download the C code from his blog (and see more pictures there and here) but I don't think there is a Windows executable yet.
