Bittorrent is currently the most popular form of p2p filesharing. See
http://en.wikipedia.org/wiki/BitTorrent for an overview plus as many details as you care to read.
In the case of this file, the TYT forum (linked in a previous post) lists Pats-TB available as a 1.36GB XVID file, one CD-sized .avi file per half so you can archive to CDs.
Can't say personally how fast or safe NFL game torrents are these days, I haven't used any since I bought a DVD recorder years ago.