Audible - Audible is the world’s largest provider of premium audiobooks and spoken word content.
Google Play Books - Google Play Books lets you search, preview, and buy millions of books using Google Book Search.
LibriVox - free public domain audiobooks
Amazon Kindle - Amazon Kindle software lets you read ebooks on your Kindle, iPhone, iPad, PC, Mac, BlackBerry, and...
DigitalBook.io - Free audio books and eBooks. Search, browse, listen, read and download over 100,000 free audio books and eBooks.
Mobilism.org - A home for book lovers, app enthusiasts, and much more.