LibriVox - free public domain audiobooks
LearnOutLoud.com - LearnOutLoud.com is the web's largest resource for audio & video learning.
Audible - Audible is the world’s largest provider of premium audiobooks and spoken word content.
Mobilism.org - A home for book lovers, app enthusiasts, and much more.
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.
Libro.fm - A digital audiobook platform for independent bookstores