Well, unfortunately I haven't found a simple way to do this otherwise I would give you some examples; however, the
tc command will do what you need.
Tc is a traffic shaping utility that is built into the Linux kernel. Be prepared, it isn't for the faint of heart. I recommend doing a good bit of reading about the queuing disciplines before starting.
At the least, this should give you somewhere to start:
From that page, this link claims to have a "simple" answer: