It's now possible for you to download the app to your own ipad/iphone or your class set of ipads, download the book(s) you'd like to read offline, as well as the audiobook that goes with it, all for free.
Here's what the website (www.gutenberg.org) has to say about itself:
"Live from Project Gutenberg with last-minute update, more than 40,000 most important books ever published in history. Plus more than 6,000 human-read audiobooks.
You can browse by language, genre, bookshelf, or search the entire live catalog.
The gate to Gutenberg treasures is finally cracked open in your mobile device! You can now wander and wonder freely among its treasures.
Listening: play in background, automatically move to next chapter. Full control through headset: pause, play, skip to next/previous track, forward/backward seeking.
Reading: The entire text is presented by a sophisticated book reader: beautiful presentation, graceful page turning, and the most intelligent Table of Contents (better than any other book reader for the same book). " https://itunes.apple.com/us/app/gutenberg-project/id672017144?mt=8
I've been using it for the past month or so, and really enjoy it. I thought you would find it helpful for yourself or your classrooms.