Here's another free doc site: snagfilms.
Oh, great site Gasket! Really good one. I'm always looking for these types of things. I'm wondering about copyright and these types of sites. Does the documentary maker give permissions to the site owner?
Short answer is yes, in the case of SnagFilms anyway. Here's an article about the biz side of the company, which was started by two guys, one from National Geographic Films and the other from AOL. The article doesn't come right out and discuss copyright, but you get the idea these guys have big enough reputations to convince directors to sign on.Along similar lines, if you like interviews with interesting people, check out TED. The site is a little overwhelming (I think), so give yourself some time to learn your way around. FORA.tv is another good site. These aren't documentaries, but there's lots of brain food. :)
Teaching. Learning. Policy. Practice. Whatever strikes my fancy.