I know this thread is a little old, but I found a program called net-peeker. I was looking for something becuase my brother had 50 downloads in kazza and 5 torrents going at once, and we have 3 other computers on the home network. Amyways I've taken a look at this net peeker and I've found it better then netlimiter IMHO. It has a global option so that you can set a global d/l and/or u/l speed or you can do it by application, you can set up bandwidth rules much like you would firewall rules. I havn't played with it in depth yet but one nice thing is that you can password protect it, which was a requirement for me. It also has a built in firewall and a few other tools, which I have yet to use.
The only downside I've found is that it's not free, but you can't have everything.
James
**I tried to post a link but it kept coming up with some sort of inappropriate site, and I'm too tired to figure out why. Just google for netpeeker and it's the first hit I think.