Sourcing video content:

On Looking at various useful sites for Visual content to aid with education I looked at three.
The first I chose because I am always interested in sourcing great content on cooking techniques for Teachers in High School teaching Home Science. The site that Harvard University has devised for sharing lectures- http://www.youtube.com Harvard Science and Cooking series: The many faces of chocolate/Lecture 3 2011 speaker Ramon Marato.  While the content is informative it is a higher level than for High School students and is designed for University students. When it first commences you see there are a lot of acknowledgements to various groups for their contributions to the making of the lecture which makes it a little dry before you get to the science of making a great eating chocolate.
The second Video site: Khan academy http://khanacademy.org "Why dividing by Zero is undefined: Thinking about why dividing by zero is left undefined. I really enjoyed the visual presentation of this site and could see this as a useful site teaching Higher School Mathematics. Why? simply the clear communication of the presenter and the great way the old "Black Board" comes alive writing as you watch!
Finally the EDU site entitled: The Olympic Altitude Advantage -  http://www.youtube.com/education
I really enjoyed this site and would probably refer teachers who were not familiar with it to have a look at the program content. I also like how you can post a comment and tweet it as well. A very clear and concise site very informative and suitable for High school students.