A podcast is a special feed that includes a reference to an audio or video file instead of just text. People use a podcasting client (such as iTunes or Juice) to collect and listen to the episodes.
Have you ever considered creating your own podcast? It's like having your own radio or TV show. Your subscribers, instead of reading your posts on their computers, can listen to your content through their headphones at any time.
Adding a podcast to your WordPress blog is outrageously easy. While generating your blog's RSS feeds, WordPress automatically adds all the required tags if a music file is linked within that post. These tags are read by podcast clients. Therefore, all you have to do is make a post, and WordPress will do the rest for you.