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.
Google Play Books - Google Play Books lets you search, preview, and buy millions of books using Google Book Search.
Downpour.com - Listen to high quality audiobooks instantly. Download audiobooks to your iPhone, Android, or other listening device. Find titles including best-sellers and new releases. Downpour, where content reigns.
Quickreader - Quickreader is a book reading application for the leading smartphones that is combining the solution of two main issues of the book readers namely book reader and availability of books from the leading publication houses.