I was notified a few months ago of the possibility of adding our extended show notes to the MP3 files that we publish daily. This is something that fans had been asking for in the past and up until then, I thought it was utterly impossible. Well, there is a way. Here's how.
The first thing to keep in mind is that adding show notes to your MP3 file must be the last thing you do to the file before publishing it to the web. If you add show notes to the file and then open it up in an ID3 tag editor other than iTunes, you run the risk of stripping the show notes away without even knowing what you've done. You can always save yourself the headache by using iTunes to edit your ID3 tags as well, eliminating the need to switch programs.
To import the show notes into your MP3 file, first import the file into iTunes. Right-click the podcast file in the iTunes Library and select Get Info. Select the Lyrics tab. Paste your show notes into this window. You might also spend a few minutes formatting the show notes so they look nice. When you are finished, click OK.
That is it, really. It's very simple, but for some reason, not commonly used. You can then publish your podcast to the web as usual, and those with the ability to see information from the lyrics tab will then have full show notes on display. I know that the Apple iPhone and iPod Touch can display these show notes. I've heard from a few others with different smart phones that can see them as well. Happy show-noting!