LibriVox - free public domain audiobooks
DigitalBook.io - Free audio books and eBooks. Search, browse, listen, read and download over 100,000 free audio books and eBooks.
Audible - Audible is the world’s largest provider of premium audiobooks and spoken word content.
LearnOutLoud.com - LearnOutLoud.com is the web's largest resource for audio & video learning.
Islamic Audiobooks Central - Listen to audiobooks about religion, spirituality and philosophy from the Islamic perspective.
Wiley Online Library - Wiley Online Library is an e-library consisting of a wide range of e-books, research papers, and publications in the form of text and PDFs.