You have to find .torrent servers. The bittorrent program will connect to something called a tracker and work like a p2p program. All users that have that .torrent file using that tracker will be open for use. For example I watch an anime series called Naruto. I use various trackers to get my Naruto.torrent files from. Just do a search on google for the kind of torrent you are looking for.
Its generally hard to find a licensed product on a tracker.. As anything licensed is illegal to download at no cost to the makers. I dont know of any underground trackers. I can only tell you to check a p2p program such as shareaza. www.shareaza.com