There are some very good sites out there that offer incredible resources for teachers to use. I like NeoK-12, where I think I could find something to use everyday in the classroom. Blip.tv and Google appear to offer video producers and publishers opportunities to do so without difficulty. Here is an sample video from NeoK-12:
With the advent of ActivBoards, the technology is very user friendly, saving teachers a lot of time and frustration. Remember the days when perusing the catalog for videos, then ordering the videos from the state Educational Region Service Center, waiting for them, then using them within the designated amount of time, replacing them in their canvas bag, and taking them to the front office for an educational region center representative to come and pick the videos up? Those days are definitely GONE!!
Here is another video. This one if from U S National Archives Channel:
Frank Capra and Dimitri Tiomkin had a part in this series of films from the Army's Office of the Chief Signal Officer.
Might I add that I really like the PBS site, as well?