Fantastic video from Luis Perez about adding alt tag descriptions to images in Book Creator. Between that, audio narration, text, and video, Book Creator may be the ultimate app for reaching all learners.
This is an interesting take on eBooks for pre-school children. Though not free, the app includes audio books, games, and the ability to send a custom report on the students' progress.
This is a great site for both streaming and downloading audio books. There are both free as well as paid for options. What's really nice is that you can listen via streaming before deciding whether or not to download the full mp3 file.