Have you installed the shoutcast server on a remote host?
Do you have the shoutcast plugin for winamp?
In order to stream audio you will need the server setup and then use either the shoutcast DSP plugin
for winamp or something like this
in order to stream the audio to a server that users then connect to in order to listen to it.
The mod I did then allows you to show the status of the radio on your forum, so any users that want to can then see if it's online and listen to it if they want to.