Satellite Radio comes in many shapes and forms.  There are two different service providers, XM and SIRIUS.  Both share the same concept as far as you pay per month and get CD quality sound and about 150 channels, most commercial free.  One of the most popular means of satellite radio is a portable solution that allows you to take your subscription between home, car, and work.  This type of setup is FM Modulated in the car, which means you have a separate screen to interface with (examples in pictures below), the clarity is not as good as what satellite radio is capable of but is still WAY, WAY Better than traditional AM/FM.  To get true CD quality you will need to get a satellite radio ready head unit and a separate tuner box.  With this you will control the satellite radio through your head unit.  The downside here is you subscription is stuck in your vehicle.  No matter which way you go once you get satellite radio you'll wonder how you lived without it.