Before downloading your first e-book, you must acquire, install, and register the appropriate e-book reader software on the computer or device to which you are downloading the e-book.
For a PC, you'll need:
Adobe® Digital Editions is a free, Rich Internet application (RIA) specifically designed for digital reading. Digital Editions enables readers to acquire, manage and read e-books and other digital publications in a simplified and engaging way.
Unlike Adobe Reader, Adobe Digital Editions is a lightweight application (4MB download on Windows). Its user-friendly interface allows readers to organize e-books (Adobe PDF and Adobe EPUB) on bookshelves, view bookmarks, annotations and a table of contents, and increase and decrease text size. You can also move DRM-pretected e-books to mobile devices including the Sony® Reader Digital Book.
To download visit: http://www.adobe.com/products/digitaleditions/
With the iPhone and iPad
You will also need Bluefire Reader (www.bluefirereader.com)
With a tablet and DROID operating systems
You will also need Aldiko (www.aldiko.com)