Now that Pandora's monthly streaming limit is history, you're free to listen to music till your heart's content. But that newfound freedom means you'll also need to be mindful of any data caps associated with your cellular contract. Apparently Pandora realizes this, as the company has now added a sleep timer to its mobile apps for iOS and Android. It's a no-frills feature add; you can choose to shut down your stream after 15, 30, or 60 minutes, and Pandora helpfully displays a countdown in case you need to extend the listening session a bit. The company says a sleep timer has long been a top request from its users, and Pandora has pledged to add more functionality to its mobile apps in the months ahead. But starting now, you can finally fall asleep to a Pandora station without worrying about being hit with data overages. There's no word yet if or when the sleep timer will make it's way to Pandora for Windows Phone.