XM and Sirius are satellite radio services. They were formerly two separate companies with different music programming, but merged in 2008. Currently, programming on both services is nearly identical except for a few programs which are proprietary to each service. Howard Stern, Martha Stewart, NASCAR radio, and NFL radio are exclusive to Sirius. Bob Edwards, Oprah Winfrey, and MLB baseball are exclusive to XM radio.To receive satellite radio, a special receiver is needed. There are a wide variety of models to chose from, depending on where the user will be listening to the radio. There are radios which are designed to be used in a car, models which are designed to be used in a home or office building, and some units which are portable and can be taken anywhere. Some radios have additional