Odeo.com
This portal, launched by the guys who created Twitter,
offers a wealth of MP3 files—3.3 million-plus at last count—and audio channels numbering in the thousands, all of it available legally for download into your mobile device, or for streaming inside the website too. Sign up for a free membership and you get access to the My Audio section, where you can create a personalized playlist that is automatically populated with fresh segments from the podcasts to which you've subscribed. It also lists the stuff you've starred as favorites and recommendations from friends. You can even subscribe to your own playlist and have it synchronized with your iTunes. Two more podcast portals to try: PodShow and Podomatic.