I have to ask: Why are you asking this question in the InDesign forum?
But I'll set that aside and point you to a great eBook about creating eBooks from either Microsoft Word or InDesign. It's by Liz Castro, and it's called "EPUB Straight to the Point." Here's a link:
Thanks for the quick and expert reply, Steve! I'll check that book out.
I got the idea from David Gaughran's book Let's Get Digital; How to Self-Publish and Why You Should that I'd need something like InDesign (he didn't mention it by name) to get the ebooks formatted optimally for various eReaders and turned into .epub and .mobi formats.
Before deciding that "InDesign IS software to create any epub with", make sure to read the "General EPubs" thread (http://forums.adobe.com/thread/848122?tstart=0).
Lots of opinions in there, the most prevailing seems to be that InDesign is currently NOT "software to create epubs with" (which, in my experienced opinion, is true) BUT nevertheless it SHOULD be (which is ... debatable ...).
(Why? Because primarily, and by design, and intention, InDesign is Document Layout software. Counter-argument: "but an e-pub is also a document!" Sure, but so is a JPEG image -- and using InDesign to create or edit JPEGs with is using the wrong tool. InDesign is great at creating Old Style "tree killer" documents. Its epub export options are not meant -- one hopes! -- to be used out of the box, but merely to facilitate a translation from a "killer tree" document towards an epub. Everything else should be fixed, enhanced, made mobi/kindle/ibooks friendly (etc.) using the appropriate software, and lots of background knowledge.)
I appreciate the insights, Jongware.