Podcasting is the next step up from blogging. While blogging is done by armies of pajama-clad ordinary people, podcasting is done by many of these same people, though less often in pajamas, in front of a digital or audio recorder. Short pieces are recorded, then distributed via RSS 2.0 or Atom to their website, typically a blog site. Listeners and viewers can then download podcasts using podcast clients. A good podcast client (for example, Juice, CastPodder, or iTunes) will allow you to subscribe to the RSS/Atom feed of your favorite podcasters and automatically download the content to a computer or to a portable audio player when new items are available.
Most podcasters create their content in MP3 or MP4 audio or video files and upload them, linking to the file in a blog post. Users can then click the link to download the content if they're not automatically subscribed to the RSS/Atom feed. The problem has never been in getting the content to the web page, but in getting the content to work through the feed systems. Wordpress, in most cases, will automatically include new podcasting data in your RSS/Atom feed system. This makes it easy for you to deliver content and for your users to subscribe to that content.
For most people, WordPress 1.5 and above will podcast easily and automatically. When you link to the audio file in a WordPress post using the full URL address, it automatically adds it to the RSS/Atom feed and makes it usable as a podcast. Make sure you use a full address.