I take it you have already seen these:
http://tutorials20.com/graphics/image-on-a-coin/
http://www.fstutorials.com/photoshop...fect/tutorial/

The trouble is that most of these tutorials have some sort of 3d effect going on, which makes it pretty much useless for animation. You could create each frame by hand of course, but that may take quite some time to get right.
I don't know what kind of style you're going for, but if I had to do that, I would use 3d software to create the coin model and the animation.