- http://www.bittorrent.org/beps/bep_0003.html
 - https://wiki.theory.org/index.php/BitTorrentSpecification
It worked pretty well. Used it for several years until I started making real money and decided I could buy things rather than pirate them.
I had only been coding for a year or two at that point, so it is probably filled with lots of odd choices, but it also isn't super optimized like I would guess the more well known clients might be, and so might be easier to parse.