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.
This free app lets you create notebooks that incorporate audio, drawings, type, and images.Its goal is to mimic a paper desk and become a notebook replacement.
This digital note taking tool leverages annotation features, audio recording, the ability to combine multiple document types and easy sharing via Dropbox or Box.
Another great digital storytelling app, there is a free version as well as an enhanced service. With the free app, you can create and share stories with images and audio straight from your mobile device
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.
New iPad app from Adobe seems to combine the best of a lot of different apps - internal image search like Haiku Deck, record audio on pictures like Speaking Photo, plus even more.
Though this is not necessarily a post specific to the iPad, many of the suggested resources either have apps or can be used on the iPad via a web browser. There are some interesting concepts for ELL/ESL or even foreign language learning.