I have a Directed Electronics HD radio (shares the same design with Visteon) hooked up to the computer using Mitch's serial cable. Audio is fed into the line-in jack on the sound card. Very good results.
The mp3car store sells Boomzbox HD radio that is similar, but with USB control. Audio is transferred over USB as well.
There are satellite radio solutions that work in a similar way. Have a look at Mitch's site: http://www.rush2112.net