I have been learning to use Rythmbox's Radio Station a little more, and found that it is pretty easy to get all of Sky.fm's radio station feeds integrated with Rhythmbox. I added the Christmas Music stream offered by Sky.fm and it was very easy to do.
Simply go to this link, and mouseover the Listen Now! tab to select the the channel you want, the MP3 streams and 96K. Once you have the channel you want selected then right click to select "Copy Link Location."
Next open up Rythmbox and right click on Radio and select "New Internet Radio Station" then paste in the link into the url window that come up.
You then have the radio station saved in your radio list. You can right click on it to change the title from the properties menu.
With a little time spent, you can get the entire Sky.fm directory integrated right into Rythmbox.