Thanks to all who have bought my Audio and Video in EPUB miniguide. The response has been overwhelming and I am really honored. I hope you're finding it useful.
Over the weekend, thanks to feedback from Barnes & Noble, I figured out how to get audio to work in both the iPad *and* NOOK Color, without having to resort to mp3 files: you create an m4a audio file and make sure to declare it in the OPF file as audio/m4a.
You might ask why I worry about NOOK Color at all if independent and self-publishers are not yet allowed to sell enhanced ebooks through Barnes & Noble's PubIt program. The answer is that I believe that it's important for your ebooks to work in as many platforms as possible. If there's a code that works in more than one place, that's the code we EPUB developers should be using. B&N doesn't accept enhanced ebooks now, but they may well do so in the future. And your books will be ready. In addition, you can always sell your enhanced ebooks on your own website, and you will want them to be usable in as many ereaders as possible. Finally, using universal code never hurts, it only helps.
I have updated the Audio and Video in EPUB miniguide to reflect this change, as well as some minor edits--including the erroneous holdover paragraph in the introduction that said I was offering the miniguide for free to current owners of my EPUB Straight to the Point book. The truth is that I dithered about how to offer this Audio and Video in EPUB miniguide right up to the last moment, although in the end, I decided not to give it away, but to sell it for $5. Sorry for the confusion.
I have sent download instructions for the updated version of the miniguide to all those who bought it already. If you don't get them, feel free to drop me a line and I'll send it to you again. I have also updated the file that is available from my store, so that if you buy the guide now or in the future, you'll automatically get the new version. It's labeled May 23, just in case you want to confirm.
As always, let me know if you have any doubts or questions.