Center for Disease Control (CDC) now offers Podcast. For those unfamiliar with Podcast–it allows you to either download selective audio files (and some video files), or to subscribe to selective topics, so they automatically download when new audio programs become available to a software program, such as iTunes (free download). You can then listen to the audio program either on your computer or with an iPod.
If you are not into all that new technology, then you can just click and listen on your computer.
Some Podcast subscription titles include: