Google video has some really good documentaries available, and they're not limted to 10 minutes like YouTube. Here's two:
The Cutting Edge - The Magic of Movie Editing looks at the art and technique of editing film, with commentary from Scorscese, Spielberg, and others.
Like Feed, Spin used satellite feed footage to expose the media-constructed reality of politics in the 1992 presidential election.
By the way, theDossier.ukonline.co.uk also has a good collection of hard-hitting & odd docs, but in low quality Real format.