You could also just buy an old tape adapter from radio shack for about $20. Hope you have a tape player in your auto. Heres what to look for: http://www.radioshack.com/product/index.jsp?productId=2361893&cp=&sr=1&origkw=tape+adapter&kw=tape+adapter&parentPage=search
I haven't found any ways that work. A better option is to use this device http://www.xm-sirius-satellite-radio.com/SIRIUS_FM_Direct_Adapter_p/fmda25.htm to make a direct connection into your radio's antenna plug. This adapter allows your satellite radio to provide clear, static-free sound. It can be difficult to install, however, depending on how hard it is to get to the back of your vehicle's radio.
Usually answered in minutes!