Controlling the network throughput

[Marcin Krotkiewski]

hi,
I'm quite aware this post is somewhat off-topic, but I couldn't find a
 proper list. Still I hope someone will be able to help me.

And here is the problem...
How can I divide my network throughput between the users (not necessarily evenly)?
I would like to limit the maximum speed with which someone is able to use my 
connection.
I tried to use something like "iptables -m limit" with no success.

I would appreciate any advice. thanks.

Marcin