How do I limit the network usage of a single application

[Brian Anderson <bikehead@xxxxxxxxxxxxxx>]

Sorry if this is an obvious question.  I googled for a solution, but 
nothing seemed to stand out that wasn't a programming solution.

I want to do some downloading without consuming all my DSL bandwidth.  
Is there a way to control the amount of bandwidth an application like 
rsync (and all its children) can consume?  I share my network with other 
computers, so I can't just use nice to control usage.

Thanks for the help

-Brian