Last month we replaced the radio/CD player in my husband's car with one equipped with SiriusXM Radio. (And yes, of course it has built-in iPhone/iPod compatibility.) I decided to look into their internet streaming, and let me tell you, I am hooked. For a measly extra $2.99 a month, I was able to add streaming to my iPad and my iPod touch. The app is free, and they will let you try it free for 30 days.
My gripe with the app? Viewing is locked into landscape view on the iPad and portrait view on the iPhone and iPod touch. That's it. View available stations by category or by station listing. Set up a list of your favorites. Hear a song that you really want? There is a button to purchase it through iTunes. Whether you like rock, hip-hop, sports or talk, you should find something you like. I like comedy and classical music, and can usually be found listening to the Metropolitan Opera Channel.
One word of warning — use this when you are connected to a Wi-Fi network. That streaming audio will eat into your data plan. The app automatically stops after 60 minutes to ask if you wish to continue listening. While that can be annoying, I've been known to fall asleep with my headphones, only to wake up in the morning with a drained battery. If you already have a SiriusXM account, look into the app.