Open Culture is a great web site that discusses cultural and educational resources on the internet. I have found some great resources on the site and today they posted a list of 50 Intelligent Video Sites.
The article has some sites that I already know about, but some were pleasant surprises.
My favorites were "Academic Earth", "Learner.org", "Pop!Tech Pop!Cast Videos", and "TED Talks."
All of the sites they list have some great material and Open Culture does a nice job describing each site.