BlogTalkRadio is the social radio network that allows users to connect quickly and directly with their audience. Using an ordinary telephone and computer hosts can create free, live, call-in talk shows with unlimited participants that are automatically archived and made available as podcasts. No software download is required. Listeners can subscribe to shows via RSS into iTunes and other feed readers. Our network has produced tens of thousands of episodes since it launched in August of 2006.
I just discovered BlogTalkRadio. They have thousands of shows on a multitude of topics, including their Heading Left political channel. You can listen online, download the programs, and they have rss feeds. Looks good.