[plug] firewalling streaming video/music?

[Joel at Plug]

Has anyone on here discovered a way of firewalling streaming video/music?

Unlike IM there's no authentication ports that can be blocked and no 
central website/s that can be blocked.

I've added the IP addresses of a couple of radio stations that I've seen 
some of the staff use but that's going to be a lot of work.

Basically just trying to reduce the amount of bandwidth used in non-work 
related activities - in our particular work environment there's no need 
for streaming services.

Joel