The iTunes Radio service is surprisingly free for all iOS 7 users, integrated in the music app as well, and will show ads to recoup some of the streaming costs. It learns what you have liked before and creates similar alternative stations for you, and can also remember your history so you have your preferred music on all devices.
That includes iOS 7 devices like iPhone, iPod Touch, iPad, but also with iTunes on Mac and PC, and Apple TV as well - moreover, for iTunes Match peeps it will not only be free, but ad-free too. The new Genius jukebox service can access the entire iTunes catalog, which, at the moment, hosts more than 26 million songs, with Sony, Universal and Warner portfolios at your disposal. iTunes Radio will be available in the US first around this fall, and gradually rolled out to other regions afterwards.