I just saw this on Lifehacker, and it's an example of the internet actually fulfilling its potential to educate. Three different types of historic films are now available from the National Archives on Google Video - NASA History, United Newsreel, and Department of Interior. This video from the Department of Interior is my favorite so far, because it shows that there was public knowledge about the need to conserve water, petroleum, and mineral resources back in 1950. Interestingly, and for many reasons, the reponse was to raise capacity, not conserve supplies, and we are now watching some of the results of those choices. Strangely topical. This video, "American Army Women Serving in All Fronts," is is fascinating as well. Hopefully there will be a lot more of these posted soon, the selection is still fairly slim.
National Archives, Historic Film