Torrents are a legal p2p sharing network, you can upload and download any game, movie, tv show, software, pictures for free.
Seed = people who are uploading the file and have the whole file
Peer/ leecher = People who are downloading the torrent, and sharing at the same time.
1. utorrent (utorrent.com)
2. azureus (azureus.sourceforge.net)
3. bitcommet (bitcomet.com/doc/download.htm)