How an iPodder works…

1. There’s a list of feeds the user is subscribed to, just like a feed reader or aggregator.

2. Periodically the iPodder reads the feeds, looks for items with enclosures that it hasn’t seen. Each such enclosure is added to a queue.

3. Another thread watches the queue, if it’s empty it goes back to sleep; if there’s something on it, it reads the first one.

4. When an enclosure is successfully read, it’s saved in a folder (user-configurable) and an Apple Event (on the Mac) or a COM message (Windows) is sent to iTunes telling it to add the file to the library.

5. The iPodder tell iTunes to synch with the iPod.

6. There’s a bit of user interface for configuration. The app runs in the background, otherwise without a face.

.When you put all the pieces together it’s as if your iPod subscribes to audio feeds, in other words, you’re podcasting

Disclaimer: I’m a Windows user so I don’t have an iPodder so I’m just guessing how it works, and hope to be corrected where it’s wrong.