Most will be using WinAmp, which allows the specification of a proxy server. You should advise those having problems to use a proxy server. Even if you serve your shoutcast stream from port 80, you're likely to run into problems. People are having trouble getting through firewalls because admins have specifically blocked shoutcast streams. If they did it by a blind port blocking, they'll notice the shift of shoutcast traffic to port 80 and start blocking specific IP addresses. If they're doing it by stream analysis, such as some more expensive firewalls do, it won't matter what port you're serving shoutcast from because it will be blocked.
If you're really determined to make shoutcast available these users, you'll need to set up a separate physical server and configure shoutcast to broadcast on port 80. You can't do this with a virtual server though, because the http server will be trying to run on the same port.
Streaming audio
Linear Mode
