I'm not sure if this has already been posted, but I just read about it on digg.
Here's the link for George A. Romero's classic zombie movie, which apparently is now public domain:
http://www.archive.org/download/night_of_the_living_dead/night_of_the_living_dead_256kb.mp4
More public domain films:
http://www.archive.org/details/feature_films
I only downloaded the first minute or so to test it, but it seems to work.
Here's the link for George A. Romero's classic zombie movie, which apparently is now public domain:
http://www.archive.org/download/night_of_the_living_dead/night_of_the_living_dead_256kb.mp4
More public domain films:
http://www.archive.org/details/feature_films
I only downloaded the first minute or so to test it, but it seems to work.