monokakata,
Thanks for answering my questions and thanks for the explanation. I have both Indesign and Quark, but my versions are a little old (pre e-book time). For me, leasing software goes against my personal beliefs so if I decide to make a e-book for Kindle I will check out the latest version of Quark and see how it goes.
I wasn't sure if it is worth spending the money on an ISBN or not? It is expensive and if I only sell a few books, it isn't worth it.
Mecha
If you're not doing print, there's no real need for an ISBN. So I wouldn't worry about it.
Check out Calibre, and see what you can push out of the older InDesign (or Quark) that Calibre can convert to an ePub.
If you're going to make an iBook, you might as well make a Kindle, and get your work up in two places at once. At Amazon, be sure to price your book at $9.99 or lower, so that you can choose the 70% royalty option.
You'll find little annoyances and differences between ePub and Kindle (the making of them, I mean). For example, the Kindle plugin for InDesign honors page feeds and tabs. An ePub coming out of ID CC doesn't, but you can set it up to operate in the same way.
I had a poet who liked to use the entire page, with lots of white space. When I made her book for print, I used spaces and tabs as appropriate and it looked the way we wanted it to. But for her ebook -- arrrgh. The pieces of text wouldn't stay put. In the end, I figured out a workflow and got it done. In the future, if I get another poet like that, I'll make the print book the way I'd make the ebook, and then the ebook would be easy.
And finally, just in case you're new to the whole ebook thing -- toss out any notion of what a page is. It's meaningless, because a page depends on the device. You still need a page feed (or equiv) for your different sections, but everything in a single section flows as one. And you don't have to waste time fixing widows and orphans. Also, joining images and captions can be tricky, and placing images where you want them on the page can be tough. Sometimes you have to make the book and then use Calibre (or equiv) to go in and edit the HTML commands.
However, you'll get the hang of it after a few tries. I don't think I've ever made an ebook that didn't require 10 or 15 versions. There's always some stupid little thing that's not quite right.
Feel free to PM me if you get something going, but it's not working right. I might be able to help.