Outdoor Research and the American Mountain Guides have produced quite a few excellent videos. If you haven't checked them out yet, log onto youtube and go to the AMGA Tutorials page.
The following video -- featuring Elaina Arenz, AMGA Certified Rock Guide and occasional AAI Guide -- demonstrates several iterations of how one might use a munter-hitch to belay. The video covers belaying with a munter-hitch, tying off a munter-hitch and lowering with a munter-hitch.
--Jason D. Martin