iPad's iBook APP
"Academic World Book now offers hundreds of the most popular e-books in two downloadable e-reader formats: ePub and Mobi. These two formats are compatible with a wide variety of portable reading devices, including the Kindle, iPad, and Nook."
EBook Collection - World Book Academic
"Academic World Book's E-Book collection includes thousands of downloadable fiction and non-fiction E-books, with selections in nine languages."