How can I resharpen serrated steak knives?

I know I could just toss them out and get new ones, but these are knives that I particularly like—when they are still sharp, of course. Obviously there is some way to sharpen serrated knives, or they would never get sharp to begin with. Even I am sharp enough to figure that out. What I’m not sharp enough to discern is how you sharpen them. But I am sharp enough to know that there’s probably somebody here on Fluther who does know how it’s done. And let’s cut to the chase. I also know there are plenty of punsters here sharp enough to have fun with the question as posed even though they haven’t a clue what to do with the knives.