My new favorite app for my iPad is actually an iPhone app (which means it is unnecessarily space constrained). I love the Public Radio app. I can listen to any public radio station in the country and even look up which shows are playing now. This is great on a Sunday afternoon when your local station insists on playing the [insert name of boring show you hate], and you would rather listen to [insert name of interesting show you love]. Right now, there are 102 stations playing Morning Edition, but there are a couple of hundred other choices from classical or jazz music to Maryland Morning to Democracy Now to On the Media to Newshour to ...
It also offers a limited number of shows "On Demand" so you can listen any time. Finally, it has some interesting features like an alarm clock and Sleep feature so you could use it in place of a clock radio.
It is a bit flaky, especially when my Internet connection is flaky so I have found that restarting the iPad helps, but when it is working, it is wonderful.
David Marcovitz