sometimes i do something like this at the top of the program:the string literal shows up in a hex editor, and you can see it in the source code. That also makes it easy to call the copyright statement in the run of the program... that way you can prove you at least had open access to the source...Code:
char*copyright="Copyright (c) 2004 John Shao";
it won't give you any real protection, but it helps to be able to show your copyright in a hex editor and a running version of the program, not to mention in the source code (if you still have it when you need to prove it's yours)
I also put in obscure comments that make sense, but only somebody that acts as immature as i do would put in... things like "figure this out on your own" and "delete this and watch the program die"