Actually, I've just figured out a way around that.
Forget gnome-schedule, it doesn't seem to do what it was designed for. Try this: go to System/Preferences/Startup Applications and click on Add Startup Program. In the Command box type the following:
For example, if you'd like a Jazz FM radio station in London, try the following:
To have the song/artist name pop up while playing:
This will launch Rhythmbox upon each boot/log in and you don't even need to press the play button.
rhythmbox-client --play-uri=http://mp3-jazz.as34763.net/listen.pls --print-playing