Hey, I listen to a lot of NPR, like KQED, KALW, WNYC, and more while traveling. It's one of my favorite news sources, only behind The Daily Show, Colbert Report, and America's Finest News Source, The Onion.
Finally, they've released a pretty good iPhone app, which I'm now using to listen to those stations. Works pretty well, only problem a reliance on AT&T 3G, which is not reliable.
You can find more details here on iPodNN including a link into iTunes to help locating and downloading the app.