Google Play Books - Google Play Books lets you search, preview, and buy millions of books using Google Book Search.
Zinio - Zinio transforms your favorite print magazines into digital format. Same content. Same design.
Amazon Kindle - Amazon Kindle software lets you read ebooks on your Kindle, iPhone, iPad, PC, Mac, BlackBerry, and...
Readly - All-you-can-read magazines on all your devices
LibriVox - free public domain audiobooks
Texture - The "Netflix of Magazines" app