As most of you know, you don't have to register your work for it to be copyrighted. The act of creating it is enough to satisfy the law. However, it is best to register with the U.S. Copyright Office if you ever wish to pursue monetary damages. This is not always the case but it is the best way to go.
As some of you also know, to copyright an image with the U.S. Copyright Office runs $30. Well, have I got news for you. In speaking with the U.S. Copyright Office by telephone yesterday regarding an idea that I had, I discovered that, according to their office, it is confirmed that you may present a contact sheet of your photos and, get this, there is no particular limitation on the size of the contact sheet. In their eyes, anything on that contact sheet is copyrighted and is covered by the law. I'm figuring that I can get several hundred images copyrighted for $30. Isn't that neat and enlightening (to say the least)? For you doubters, don't take my word for it. Call the copyright office and find out for yourself. You can also fill a CD with low-res JPGs and batch register that way.
I hope this will encourage more photographers/artists/painters, etc. to register and protect themselves. This is an issue that has come up many times on this forum and others.