BitTorrent
http://www.versiontracker.com/dyn/moreinfo/macosx/18286
Tomato Torrent
http://www.versiontracker.com/dyn/moreinfo/macosx/22891
Azureus BitTorrent Client
http://www.versiontracker.com/dyn/moreinfo/macosx/22820
Bits on Wheels
http://www.bitsonwheels.com/