Sean McMullen's Moonworlds Books (Voyage of the Shadowmoon, Glass Dragons, Voidfarer) aren't exactly comic fantasy, but they're funny in many places and very engaging, more so than much of the "serious" fantasy I've read. The second book has some especially-amusing moments.
If you can get your hands on a cheap copy, Eve Forward's "Villains By Necessity" has some amusing bits as well.