Limit File Sharing Applications

I wish to limit upload and perhaps also download of data to the WAN from file sharing applications such as Lime Wire and Kazaa on the LAN. How can this be acomplished?

A Linksys BEFSX41 router with firmware 1.45.7 is being used as the gateway and all computers are using Windows 2000 Professional with Service Pack 4.

Most torrent apps allow you to set a max upload/download.

But what may be done without physical access to the computers with the P2P software?

Route your internet connection through a customizeable router like ipcop. Then you can do a lot of traffic shaping.