DavidB let me know about Mediafly and I was suitably impressed. The app is in beta for the BlackBerry and lets you select podcasts you wish to listen to on your BlackBerry. These podcasts will automatically stream to your BlackBerry. If they do not have your favorite podcast listed you can add your own custom channel.
Note: Currently the app only supports the Bold, Curve, Pearl, & Storm devices. You also need to set your APN sometimes to get it to work.
You can pick up the app from your BlackBerry OTA at www.mediafly.mobi