Download/install/run µTorrent Use the search box to find the required movie. Download the torrent file Click 'File' > 'Add Torrent no default save..' and load the torrent. The program includes a Help File Downloaded files can be - but are not restricted to - avi, mpg,rar http://www.utorrent.com/
Very old article but some good info: http://www.dessent.net/btfaq/#what I'd add get yourself some kind of IP blocker like PeerGuardian or it's Vista rc1 version: http://phoenixlabs.org/pg2/ Good search engine here too: http://btjunkie.org/