The video is in Danish but the link is good and in English

http://www.labnol.org/software/epub-format-ebooks/10879/

How to Create ePub eBooks

If you want to publish your own books or blog in ePUB format, the easiest option is that you compose the text in Word (or Google Docs), save it as an RTF file and then you use Amazon’s Stanza program to convert that document into an ePUB ebook.
Before publishing, you should also use the EpubCheck tool from Adobe to make sure that the markup in your ePUB file is valid after conversion.
Alternatively, you may use the free Calibre program to convert virtually any document format into ePUB in a batch. Calibre is available for Linux, Windows and Mac OS X. And for editing ePUB files, you should try Sigil – a WYSIWYG editor that also runs on Windows, Linux and Mac and support the.

http://www.youtube.com/watch?v=qg9REjc1tt0&lr=1