calibre is a free and open source e-book library management application.
dotEPUB is a browser bookmarklet (or favlet) that tries to get clean text content and metadata from webpages to ease the automatic e-books conversion.
ePub ebook reader written in js
Pure web app e-book reader for iPhone and Android. Install it on your iPhone home screen and it acts like a regular app, including the use of local storage for your saved books.
Convert LRF (Sony BeBB) files to EPUB, PDF, RTF, and HTML. Also converts PDF and DOCX to EPUB.
Sigil is a multi-platform WYSIWYG ebook editor. It is designed to edit books in ePub format.