Live365.com is already at the market for a while, but was not listed at the directory. For sure it is a good tip for the weekend.
Live365.com offers a broad choice of channels and the opportunity to start an own station. The latter happens by uploading mp3 files or by playlists. There are a lot of further services available like social networking and widgets to embed a radio player on other sites.
Similar services are available at internet radio and music sharing.