I just rediscovered how to do this after knowing it then somehow forgetting it long ago.

If you listen to streaming radio with iTunes and can’t be bothered to do one of the various methods of finding the station in iTunes, this is the tip for you. You don’t have to use iTunes to start your stream; in fact iTunes need not be open.

Tested with iTunes 4 and iTunes 7; should work with 5 and 6 also.

1. grab a radio icon from iTunes
   
2. drag it to the Documents half of your Dock, it will take on the Web address Mac OS icon
   
3. click on it
   
4. that will open a web page in a browser and trigger a download of a file called something like listen.pls edit: name depends on the radio station
   
5. drag listen.pls to a nice location for long-term storage, then rename it and drag it onto your Documents half of your Dock edit: after renaming the downloaded file, Get Info -> Lock it

   

That’s it, all done. Enjoy.