Hello,
Jutoh is an inexpensive WYSIWYG ebook editor for Windows, Mac OS X, Linux, FreeBSD and Solaris x86. You can try it out here:
http://www.jutoh.com
Jutoh imports from Epub, OpenDocument, HTML and text files, and can create books in Epub, Mobipocket, text, OpenDocument and MP3 formats. Jutoh has a cover designer with a selection of templates for creating your cover image with minimal effort, and has several features for tailoring your books for different publishers and sites without the need to maintain different versions. It can also store notes, pictures and URLs in project files without affecting the generated book.
It's suitable for fiction and other books that don't have very complex layout requirements.
I hope it's of interest!
Best regards,
Julian Smart
Anthemion Software