Ok. So here you are, on your shiny GNU/Linux and dont know how these "torrents"  work.
Ive been testing a LOT of bittorrent clients and now im gonna guide you through my absolute favorite
one, just read ahead and you will know all abaut downloading uploading and setting some basic
settings.
rtorrent, http://libtorrent.rakshasa.no/
(screenshot på guiet)
So if you used MPLayer before this wont be to hard for you, as the usage with the keyboard is
somewhat the same.