NPR's mobile service, m.npr.org (which you're often routed to if you access www.npr.org from your mobile) lets you listen via live stream on your smartphone or PDA or - even - dial a dedicated line to hear the story of your choice via a phone connection.
Check your data package to see whether radical cost difference might influence your choice. You'll want to have an unlimited plan if you do a lot of streaming.
In addition to the day's top news features, the mobile NPR site offers fun stuff like a Wait, Wait Don't Tell Me news quiz you can take and then send to a friend. Story of the Day and Song of the Day are also accessible from the mobile home page. Just another way to feed the habit-but don't let it sway you from contributing locally at pledge time.