PBS Video – great place to find high quality documentaries on US History

Snag Learning and Snag Films

Documentary Heaven – free site that has organized more than 1600 documentaries sourced from a variety of services including, but not limited to, YouTube

Documentary Tube – catalogue of full-length documentaries found on the web.  Doesn’t actually host the videos rather it catalogues them thematically and displays them through embedding.

Film Story

Smithsonian