Lei Wang at the Yale Medical Library has made a great series of tutorials. Check out his work here.
He also has a presentation in Slideshare where he discusses his work.
TechSmith (makers of Camtasia & Jing) have a rotating series of videos made using their products.
Arizona State University Library Minute: The best library quick videos I have seen. ASU videos have high production values and are quick and engaging and fun.
Kimbal Library Insrtuction videos using white board fast drawing animation. Great, short tutorials.
WhiteBoard Animated Tutorials (Kimbel Library)