I actually do not have experience with this yet, but it is definitely on my to-do list this year. Here seems to be a pretty simple tutorial on the process at Education QR Codes. You can also use the app Audioboo to assist in QR code creation. I think this will be the method I use. Technochalkie explains a bit how to do it. While searching, I found a really cute idea for practicing sight words with audio QR codes by Technology in Early Childhood.
Ways to Use Audio Texts in the Classroom:
1) Create a QR code of a child reading a book. Affix the code to the book so that future students can listen to their classmate read them the story.
2) Practice sight words, numbers, foreign language words, etc., and have students check themselves by scanning an audio QR code with the right answer.
3) Students can review a book. Attach a QR code of the review onto the book, so students can listen to it and make an informed decision about reading the book.
4) Students could orally give information they have received on any subject. This could then be attached to a poster (i.e., specific planet, famous person, types of clouds) that they have created to accompany the topic.
What else??? I am very excited about exploring this type of QR code this year and would love to hear some more ideas!