I just worked up a book as an html file (which is what Amazon/Kindle requires for upload), and an epub file (which is what a lot of other sellers use). I uploaded the book to Amazon and it seems to have come through the process fine. It's for sale now as an ebook.

The other file, the epub, I believe I'll upload to Lulu.com. They sell print and ebooks on their site, and they distribute to other sellers (the two I'm most interested in are Barnes & Noble and iBookstore). Amazon/Lulu seems to be the way to go for maximum exposure.

Some people like Smashwords, which takes your file and puts it through their "meatgrinder" and then distributes to a dozen retailers, but the meatgrinder is pretty rough on documents. No telling how they'll look when they come out. Lulu seems to be a good alternative to Smashwords.

Lulu is primarily a print operation, and I believe they can turn your ebook into a print book. Not sure of set up costs or minimum runs and all that. They provide a free ISBN for ebooks and I expect they do for print books as well. If my ebook sells well I may look into doing a print run.

Formatting is tricky. I used MS Word (word processor) and Kindle's manual to figure out the formatting for the Kindle book. It's not going to impress anyone with its professionality, but it's pretty good. I'm satisfied, at least. For the epub document I used Sigil. It's pretty user-friendly.

And I worked up a cover that's not Rembrandt but is serviceable.

Ask away, anyone, if you have particular questions. My knowledge is limited to the project I'm working on, but I've learned a LOT through trial and error.