What about using
http://caster.fm and setting up a password for the player. Caster.fm allows for private broadcasting and best of all it is a FREE service that provides for both Private and public use depending how you set it up. Or you can use a Shoutcast server and just uncheck where it says list it in the directory. Then it would be for members only (see my sig for a good cheap Shoutcast server. Other than that I am not sure but I think
http://caster.fm is what your looking for.