Public Radio Tuner is a free app that gives you fast, live access to high-quality radio programming on hundreds of public radio stations, in your area or from anywhere in the country--even over slower EDGE connections. This excellent, easy-to-use app has added many refinements since its introduction, and you can now browse by state, search for call letters or other descriptors, find local stations using your device's GPS location, and easily create a list of favorites.
Public Radio Tuner isn't a general purpose radio tuner, though--it can only help you listen to public radio stations, primarily with NPR and PRI-type programming, although Public Radio Tuner also gives you access to some public radio music stations, such as KEXP. Future versions promise even more features, including access to on-demand content, but the one major limitation currently is that the iPhone OS won't let you listen to a stream while using your device for anything else (unlike, say, when you're listening to a podcast of an NPR show on your iPod). This app is still a must for public radio listeners, though, especially fans of shows such as All Things Considered that aren't available as podcasts.