Calibre-Install the ebook management in Ubuntu Linux
sudo apt-get install calibre
Microsoft Reader uses the .lit format for it's ebooks ;
Calibre is a free ebook management that works on Linux, OS X and Windows.It is meant to be a complete e-library solution and thus includes library management, format conversion, news feeds to ebook conversion, as well as e-book reader sync features and an integrated e-book viewer.
Calibre can be found at http://calibre.kovidgoyal.net/.