Lake Sumter Community College Libraries has posted several video tutorials on its Databases A-Z page. Of interest to health sciences libraries:
Michigan readers may also find Infotrac Onefile useful. (A number of Gale databases are available to Michigan residents through the Michigan eLibrary subscription; see the Library of Michigan for details, or MeL.org.)
James Cason, the librarian who put the CINAHL and Cochrane tutorials together using Camtasia, notes on davidrothman.net that keeping up with vendor changes is the biggest challenge in making tutorials.
Also on davidrothman.net, Introduction to the Cochrane Collaboration (Slidecast) and CochraneTube — a couple of videos explaining what Cochrane is all about.