Screen Capture with Jing
Jing is a free software application from Techsmith (OS X and Windows) that allows you to take screenshots or videos of your computer's desktop, which you can share over the web.
Videos (which can be full-screen or a small segment of your screen) may be up to five minutes in length and narrated. Screenshot images can be annotated in a preview window.
Some uses for Jing may include capturing and sharing tutorials, demos, or lectures. Once you've captured your images or video, you can output them to sites such as Screencast.com and Flickr or save them to your hard drive. Check out the Jing Help Center for more information.
Related entries:
Resources for Video Production at Columbia (and Beyond)
Sharing a Screen Simplifies Support
Screen Sharing for Tech Support or Teaching at a Distance
Screencasts for Student Training
Screencasting - DIY Tools