From Free Tech for Teachers: USGS Multimedia Gallery
The USGS Multimedia Gallery contains large collections of educational videos, animations, podcasts, and image galleries. You can search each collection by topic and or keyword tags. RSS feeds are available for each gallery. In addition to the videos in the USGS Multimedia Gallery you can find many videos on the official USGS YouTube channel.
Great opportunities for teachers to add interest to lessons and for students to find resources for projects.