Windows and Mac users may also download Adobe Digital Editions for an excellent PDF reader system or just use any PDF reader such as Adobe Reader or even Preview on the Mac.
Foxit has an eBook Reader and Adobe has an ebook Reader for Windows.
Download Digital Edition 4.0.3 Macintosh (19.2MB)
Download Digital Edition 4.0.3 Windows (7.7MB)
 
Adobe has an ebook reader at App Store
Adobe has Windows
Adobe Windows, Apple Downloads Getting Started with Adobe Digital Editions (EPUB, 64 KB)