The final stage in publishing an ebook is formatting it. This used to be a pretty simple deal. Essentially you converted your file to HTML added a couple of tweaks and the cover art, all zipped into a single file.
Amazon's Kindle is no longer that simple. Amazon now insists that book submitters use the .ncx file format to submit the table of contents. Ncx is an XHTML format for tables of contents, so it's sorta HTML, but not quite.
This has the advantage that it allows things like a hyperlinked table of contents for the talking book version. It has the disadvantage of being so arcane there's little information on how to do it available.
Fortunately someone stepped up to the challenge. April K. Hamilton, author of "The Indie Author Guide to Publishing" (good book) has come out with "The Indie Author Guide For Publishing For The Kindle With Amazon's Digital Text Platform, Mobipocket Creator And MS Word 2003 Or Higher." In it she walks you through the steps involved in taking your book from a text file to a ready-to-submit zip file.
Hamilton is owed a vote of thanks by everyone in the e-authoring community for untangling this tangled tale. Be warned: The process still isn't easy, but at least you can more-or-less understand it.