This is what I use:
http://www.netlimiter.com/
And not that I condone this sort of behaviour, but. here's a torrent for it:
http://66.90.75.92/torrents/1061/Net...ck-rar.torrent
Can cap upload and download speed as a whole, or on a per application basis. It's the shit.
Also, since you're using Bit Torrent for downloads, you could use a client that allows you to set max up and max down speeds. I personally use BT++ and it's great.
http://btplusplus.sourceforge.net/
Hope the info is useful.
- The Broken Monkey