calibre is a free & open-source e-book library management application developed by users of e-books for users of e-books. It is available for Windows, Mac OS X & Linux.
calibre also converts to EPUB, FB2, OEB, LIT, LRF, MOBI, PDB, PML, RB, PDF, SNB, TCR, TXT formats, from multiple e-book formats such as
CBZ, CBR, CBC, CHM, EPUB, FB2, HTML, LIT, LRF, MOBI, ODT, PDF, PRC**, PDB, PML, RB, RTF, SNB, TCR, TXT.
calibre also syncs with e-book readers, and has full support for the SONY PRS line, Barnes & Noble Nook, Cybook Gen 3/Opus, Amazon Kindle line, Entourage Edge, Longshine ShineBook, Ectaco Jetbook, BeBook/BeBook Mini, Irex Illiad/DR1000, Foxit eSlick, PocketBook 360, Italica, eClicto, Iriver Story, Airis dBook, Hanvon N515, Binatone Readme, Teclast K3, SpringDesign Alex, Kobo Reader, various Android phones and the iPhone/iPad.