calibre is an e-book library manager. It can view, convert and catalog e-books 
in most of the major e-book formats. It can also talk to e-book reader 
devices. It can go out to the internet and fetch metadata for your books. 
It can download newspapers and convert them into e-books for convenient 
reading. It is cross platform, running on Linux, Windows and OS X.

For screenshots: https://calibre-ebook.com/demo

For usage instructions please see
http://manual.calibre-ebook.com

For source code access:
bzr branch lp:calibre

To update your copy of the source code:
bzr merge

Tarballs of the source code for each release are now available 
at http://code.google.com/p/calibre-ebook