http://jaycut.com Online video editing. Easy.
http://khanacademy.org Not much history...yet. Awesome for math and science though.
http://wikispaces.com I used this back in 2007 with a government class during a chapter on the President.
http://aviary.com Online editing of anything. Only limited by your imagination. You can create the soundtrack to your video with MYNA- so cool.
http://snaglearning.com Quite a bit of recommended viewing you can do here. I just watched this.