Podcasting—a popular topic among these PR-focused blogs lately—is about listening to amateur-produced radio shows when and where you want to. Today, XM Radio announced a new product, the Delphi MyFi. This pocket-sized, wearable receiver gets all 130 channels of XM satellite radio. Here’s the catch: It also records up to five hours worth, either while you listen or based on programs you schedule for recording.

I noted here a couple weeks back that podcasting would be big when XM and Sirius made their broadcasts (like Bob Edwards’ show) available as podcasts. This is an even better idea—sort of Tivo for the radio. The only problem is that you can’t use the device for other digital audio files. But with this product hitting the market, it’s only a matter of time before the two come together.