Well, running a server requires a lot of bandwidth, especially if you have a lot of listeners, so you may want to google around and see if you can find a publically available shoutcast server you can use. I don't know of any right off, but I'm sure there are some available.

If you have a hefty internet connection (fast upstream) and/or you don't have more than a few listeners, you could run the server on your local computer and either stream to it from your client or load a list of songs into the server. If you were to choose to run your own server, you would need to make sure any router/firewall on your network had the proper ports open.

You may want to read through a guide online as it will provide more detailed descriptions than I can here:
http://webmonkey.wired.com/webmonkey...?tw=multimedia