You can use Calibre to extract an OEB version, or MobiPerl's mobi2html. However, the MOBI format isn't designed to be human readable. MobiPocket takes an OEB ebook (the best example now is an ePub, but a collection of HTML and images also works) and smashes it down to a dumb as dirt single-file HTML with custom add-ons version.
What you really want is the original OEB version, which is saved if you use MobiPocket Creator, but does not help someone trying to work backwards from the MOBI.
Unless you want to add DRM, what I suggest is to produce an ePub version and then run Calibre to convert to MOBI. Some ePub features get lost, but a surprisingly large number get through. You can look at how an ePub is constructed simply by unzipping the .epub.