A friend recently asked me how to sharpen a serrated knife, and I realized I had no idea. I sharpen my chef's and paring knives at home on my sharpening stone. But I've never sharpened my serrated blade. Poking around online, I found a link that says you can sharpen on a stone by each individual blade serration. That sounds insanely time-consuming. Other sites say it should only be sharpened by a professional.
Anyone have any suggestions for how best to sharpen a serrated knife?
Update: Doh! Forgot to turn comments on. Fixed now, answer away.