Adobe’s PDF format is the most widely used e-book format used. You can convert from PDF to html for epub or mobi. The best way to format for EPUB or MOBI is to start with a well formatted word document. All PDF conversions will require html cleanup.
How Automated eBook Conversions go Wrong (Mobi EPUB)
I don’t have to tell you that the ebook industry is exploding. Everyone seems to be putting out a book. Unfortunately, many of these would be authors will have problems with their ebook output they didn’t foresee, simply because they didn’t familiarize themselves with how an eReader works.