Satellite radio is coming and there are two main companies providing services. XM Radio Holdings (as mentioned) is one of them. The other is Sirius Satillite Radio. It's the mobile radio equivalent to cable TV or satillite TV. You'll have to pay a monthly fee, like $10-13, but you'll get a large number of stations of varied formats. You'll also be able to keep the same station across the country.
GM and Porsche are among XM's clients while Sirius will supply service to DaimlerChrysler, Ford, and BMW.
I'm not a fan of "another monthly payment" either, but that's the way the world is going. All of those bargain computers get you with monthly service charges to AOL or MSN. Cars will be similar with charges for satillite radio and OnStar (or similar systems) and mobile phones and navigation systems and....
Someone proposed to the auto industry (not too long ago) that they give away their cars in exchange for all of the monthly charges that will come with cars in the near future.