How does this work? What kind of program do I need to download a torrent?
The torrent is a 55kb file with a bunch of server addresses, and you run it with a torrent client (list of clients in this FAQ but personally I'm partial to uTorrent). You can get the movie documentary torrent from the above link ( http://www.mininova.org/get/617122 ) and then you use the torrent with the client to download the movie. It's pretty straight forward --if you're running your internet through a router then it helps to assign a port but that's a different problem --Freepmail me if that comes up.
Good luck!