Calibre is a free and open source e-book library management application developed by users of e-books for users of e-books. It has a cornucopia of features divided into the following main categories:
Syncing to e-book reader devices
Downloading news from the web and converting it into e-book form
Comprehensive e-book viewer
Content server for online access to your book collection
For Windows 32 & 64 bit, OS X, Linux & Portable
Get it HERE.