Question : Blocking Internet radio

I am wanting to block users from using the internet to listen to the radio as its using up loads of my bandwidth.

Is there any ports I can block or is there some other solution.

Answer : Blocking Internet radio

well the problem that your going to have is finding what protocol they are using as web radio could use many different web protocols.
what you need to do is sniff your network to see which protocol is being used and block that using ipsec on the client via group policy

http://support.microsoft.com/kb/813878