Last week we were all calling it Google Editions, but now their ebook download store is known as Google eBooks. It's available now for Android and Apple devices as a free app, with the three million books varying in price.
As Google is wont to do, Google eBooks is pretty open, able to be used with many different devices (though it seems it's just Android, Apple, Sony and Nook portables for now). The books are stored in the cloud, in a Google eBooks account similar to a Gmail set-up, where you can read books on laptops or tablets right there in the browser. Storage is unlimited, and there are over three million books to choose from now. [Google eBooks]