A Podcast is a collection of audio or video content that's powered by subscription software called RSS. Just like a magazine automatically gets delivered to your home when you subscribe, a podcast delivers new content directly to you -- without you having to check on the Web site for updates.
When you subscribe, you can go directly into your podcast software and have it search for new content. All the latest Podcast updates will automatically get downloaded for you. You can then choose to listen or view the content right then, or download it to a portable listening device for later viewing or listening.
For a listing of all NASA portal podcasts, please visit the NASA podcast page at: http://www.nasa.gov/podcast