streamtuner is a stream directory browser.
Through the use of a plugin system, it offers an intuitive interface to Internet radio directories such as SHOUTcast and Live365.

With streamtuner, you can:
  • Manage your local music collection, with full support for ID3 and Vorbis metadata editing
  • Listen to streams, browse their web page, or record them using programs such as Streamripper
streamtuner can be installed directly from the Linux repositories or from the webpage.

Other applications:
vlc (VideoLan-Client) contains also access to a huge directory of online streaming services like streamtuner. You can find it inside the playlist editor. (haven't checked this yet if it is available also on the Windows port of vlc.)

The main difference:
streamtuner doesn't play itself the radio, but uses your preferred multimedia player. For example, I use the default Totem Movie player on Ubuntu.