Since hosting a stream is expensive, and requires lots of bandwidth, and for the most part needs to be dedicated, I'm in the process of building a vending machine in SL to give out time on my server for shoutcast/icecast based audio hosting.
Basicly something you walk up to, pay the machine so many $L and I wisper you back a password and media url, as well as give you a box to set the media url on your land and possibly recharge your access to the server. Depending on the package, you can have so many listeners, at some bandwidth (64k, 96k, 128k), and for some ammount of time (1 hour, 2 hours, 1 day, etc). All you need is some software to stream up to the server such as one of the winamp plugins or one of the hundreds of pieces of software to stream an mp3 or ogg stream.
I'm thinking this should be a great service for live events and people with clubs. I'm wondering what you guys think?