Jing is part of the TechSmith suite and is a free and simple tool to capture, edit, and share screenshots and video.
Screencast.com allows you to store and share screencasts easily.
SnagIt is a tool to capture, edit, and share screenshots and video longer than five minutes and offers greater customization.
Here are some quick tips and best practices to keep in mind:
Library Minute from Arizona State University Library. Short video examples.
5 Things to Know about the Medical Library, produced by Yale is a great example of paring down and defining what are the most important takeaways users should know about our libraries to be successful.