Please disregard this message if u r already familiar with bittorrents.
just FYI i've been using bittorrents for last couple of years to download all the hollywood and bollywood movies for free and u can download either xvid, svcd, cam rip and other qualities depending upon your taste. there's tons of movies, music, games, porn, tv shows yada yada yada and there's a tons of torrent portal sites. i'm listing a few

bittorrent tutorial

http://wiki.theppn.org/index.php/BitTorrent_Tutorial
http://www.methodshop.com/tech/articles/downloading/bittorrent/index.shtml

u will need a bittorrent client like azureus, abc, bitlord etc. i like azureus the best. download azureus at
http://azureus.sourceforge.net/

torrent portals

for hollywood stuffs

http://thepiratebay.org ( this is the biggest portal these days i think, requires no registration)
http://bitsoup.org (requires free regiistration)
http://torrentleech.org (requires free registration)
http://torrentit.com (requires free registration)
http://empornium.us ( WARNING: this is a porn torrent portal, u have to be 18+) (requires free registration)
http://pornbits.net ( WARNING: this is a porn torrent portal, u have to be 18+) (requires free registration)

for bollywood stuffs
http://bwtorrents.com (requires invitation to register)
http://desitorrents.com (requires invitation to register)
http://imtorrents.com (free registration)
http://desiclub.in (free registration) (currentlyl site is down)
http://idesir.com (free registration)
http://indiantorrents.net (just a desi forum site)

Is it legal?

I just use Ares. you can get it at ww.aresgalaxy.org.
Just like napster.

talking explicitly it is not legal to download the copyrighted materials by any means, but there are millions of users worldwide sharing copyrighted materials thru bittorrents so it's upto u if u wanna use it or not. also bittorrent technology is perfectly legal and started as means of sharing large files easily but sharing copyrighted materials w/o owner's authority is perfectly illegal. FYI one third of the total internet traffic is the bittorrent traffic these days.