Likewise, as I have helped to build flipcharts for Ancient History the History channel site was invaluable. I also worked with my 5th graders on projects about American History and used video clips from the History channel. Students are able to manipulate these easily and quickly.
Both of these have search features that are fairly easy to understand and use. I have used them even with kindergarten students. It is imparative that you watch the entire clip as sometimes there are things included that you might not want to use or the clip strays from your subject and might not be the best choice.
The new seach engine that I found is Kool Touch. First please read about it in this article. You will need to scroll down - it is the featured New Search Engine of the month. I am adding a few screen shots.
This is what your search yeilds.
Next you click on the numbers.
When you let go, the video section will open and you can click on a variety of videos on that site that go with your subject search.
This is only one of the many new search engines that are being created.