I wrote about the Smashwords submissions so I suppose I should add what happens on Amazon too. It looks more professional than Smashwords but the time it takes to be approved even for additional updates is quite annoying. This makes it hard to have a simultaneous release on both sites. Smashwords is easier to use and from what I've heard about the emails people have gotten from Amazon when their book has been refused, it's harder to tell why it hasn't been accepted. Personally, I felt that the process at Smashwords was easier but I'm sure lots of people prefer Amazon.
Submitting an Ebook to Amazon's Kindle is relatively simple using Amazon's Digital Text Platform (DTP). You create an account (or use your existing Amazon account) and go to your dashboard. It's actually called My Shelf and any books or drafts you have remain here to be updated or removed whenever you like. Once you have fully uploaded a book, it takes a couple of days to be accepted and then another day or two to go live. Every time you edit a book here, it takes the same amount of time to go back on sale again which is a little irritating.
There are no real guidelines on DTP so you have to be aware of what looks professional and what doesn't. Assuming your book is ready to be published, you need to fill out the Product Description first of all. You need a title, a description and the name/s of the author/s. It's great that you can add author's names to this very easy - handy if it was a collaboration. The actual description isn't obligatory but it fills in for a blurb so use it and make it work for you.
Next up, you fill in the name of the publisher, the ISBN, the publishing date and the language. It is not necessary to fill in a publisher's name or an ISBN which is handy for those of us who have neither. Keywords and categories are the next requirements. Be sensible, be relevant and don't go overboard. You can now add an Edition Number, a Series Title and a Series Volume but again, you don't have to.
Finally you choose your DRM options and upload an image. You either enable or disable Digital Rights Management. I didn't choose to enable it. The image is your book cover - obviously. Use a decent cover and try to resize it like a Smashwords cover, as in book size. There is very little in the way of guidance on Amazon which I feel is silly because they should help those who aren't in the know create the best product they can.
Once you are happy with all of the above, you click save entries and it automatically takes you to the next step.