Shoutcast can be used to stream audio content across the Net, however you cannot use Windows Media Encoder as a source.
You need Winamp (free) and the Winamp Shoutcast Plugin (DSP - also free) to make a source.
Set those up and you're half way there. Next step is to download shoutcast and install it, and run it. Note that if you try to do this on a webserver and the owner of the server does not intend that it be used for this purpose, you might not be successful. Talk to your hosting provider about whether shoutcast is supported on their systems.
If it is, once installed, you need to edit the config file (See the readme that comes with the download) and change your password. Usually, no other changes are necessary. Once you have saved that change, start Shoutcast.
Now in Winamp, set up the DSP plugin with the IP address, port (8000) and password of the shoutcast server. Play some files to make sure it connects and is working.
To listen to the stream, you would go to
That's it - (The .pls file is created automatically)