The Flip Ultra is an very compact, easy-to-use video camera. It captures 120 minutes of video on 4GB of built-in memory. There's no tapes or disks to worry about and it runs on 2 AA batteries. The Flip has pre-loaded software for instant viewing, editing and sharing the videos.

Flip Ultra Quick Start Guide
6 Recommendations for Teaching with the Flip Video Camera
A Few Tips & Tricks for Student Filming in the Classroom
Flippin' Out - article from THE Journal

43 Ways to use a Flip Camera in the Classroom by Tom Barrett

The Many Ways to Use Flip Video Cameras in the Classroom by Richard Byrne.