Spotify’s iPhone app is a great way to listen to unlimited streaming music on a radio station. However, on-demand play requires a premium account, which is a smart business move on their part. Regardless, having streaming music at your fingertips is pretty awesome and desirable. The stations are grouped by artist or genre, and listeners can discover similar, but new songs they haven’t heard of before. It’s also a good business move to require a premium account since that’ll most likely incentivize people to join.