I’ve written up a tiny little FAQ for people who use the stock BitTorrent client with OSX, and are tired of having it eat up all of their bandwidth. I discourage use of my own hack which limits BitTorrent to 1k, and a single user; that’s just not fair – most of us aren’t on 28.8k modems!
CarraFix looks nice, but it requires you to leave it open, whereas with OSX’s UNIX native system, the background throttled process is much more elegant to a geek like myself. ;)
The faq is available here.
Update: I’ve looked at the beta release of BitTorrent 3.2.2 (Official) for OSX, and although a bit quirky, it had user-definable parimeters for bandwidth useage, maximum peers, and even the ability to set your IP address reported (for use with funky network configurations, NAT, et al); thankfully this will hopefully eventually render this little FAQ obsolete.