bit toreents are basically a new p2p.
you don't log onto anything... but it works kinda like kazza. you DL from 2312 people who have torrent software, but theres no interface or anything.
its a url: somesite.com/torrents/something.torrent
and from there, it DL's like a normal file would- but the host files are hosted by 1000s of folks who have the same file