Or check out the specification at bittorrent.org: <a href="http://webcache.googleusercontent.com/search?q=cache:Dm_oT-YzmiYJ:www.bittorrent.org/beps/bep_0003.html+&cd=3&hl=en&ct=clnk&gl=us" rel="nofollow">http://webcache.googleusercontent.com/search?q=cache:Dm_oT-Y...</a> (site was down when posted...)