It may be a little late for me to weigh in on this one, but I've just published an ebook (http://www.hearmysoulspeak.com) on Kindle within the last couple weeks, so I figured I'd offer my own experience from a different angle.
I'm not a traditional published author. This is my first book. Using the logic that an ebook has numerous formatting considerations that make it easier (far less worry about page numbers, page size, left/right concerns, etc...), I decided to go with the ebook in the hopes of making enough $$ that it'd be worth my time to properly format a print book.
The book is about Shakespeare (specifically, a collection of Shakespeare wedding material), and I knew two things - I should have some sort of credentials in the area I'm writing about, and some sort of way to market. I run a number of Shakespeare sites (http://www.shakespearegeek.com primarily among them), and have done so for a number of years. They've got a pretty good following. I thought I'd be all set there, at least as far as getting a jumpstart goes. I'm also a web guy for a living (though not a designer), so arranging a domain and getting some content on it was not much of a worry (http://www.hearmysoulspeak.com did I mention that?) My strategy has been "Have something acceptable up, then drive traffic, and then once you've got traffic up, worry about making a prettier site."
I did have an editor. You need an editor. You will make stupid typos, if nothing else, and you'll need another set of eyes to spot them. An editor also serves as your first reader, and can say things like "This part didn't make sense to me" or "You said the same thing here that you said over there." Get an editor. I lucked out, one of my regular readers who happens to be a college professor said he'd do it for me, and was very helpful.
The publishing part is actually the easiest. There are a zillion "ebook converter" apps out there. But instead of doing that, just go straight to Calibre (http://www.calibre-ebook.com), as it does everything. I originally started mine in LaTeX, because I was heading for print. Then I switched to PDF (easily converted) until eventually ending up with EPUB since it seemed popular. EPUB, for the curious, is basically just a zip file of HTML with some organizing context thrown in). See below, though, for thoughts on how to handle multiple formats.
Here's the tricky part of publishing, even if you do crank out multiple versions of your book : a) every publisher wants a different one, and b) you have to do it individually for each. I started out on Lulu, because that was the most efficient way I saw into the iPad store. iPad wants EPUB. Fine. But then I wanted to release a PDF version as well, to cover the wider case for people reading on a PC. Lulu can handle that - but it can't apparently associate them both on a singe page. So I'll forever have two products in their catalog. I can live with that.
Aha, but what about Kindle? Kindle has its own store, for one. And, it wants MOBI format. Ok, did that. Now I've got to maintain my book in two places.
Guess what happened last week? Barnes and Noble opened up their Pubit! store for the Nook. Yayyy, three places to maintain my book. I hear Borders has a project in the works as well.
I generated every format (EPUB, MOBI, PDF) of my book in Calibre, and then tweaked them by hand until they looked the way I wanted (or at least, as close as I could get). Although all of the ebook stores will do automatic conversion for you, keep in mind that your copy will end up looking terrible.
Your pages on all these stores will also look very plain, until you get some reviews. Seriously, go get some reviews. Give away as many copies as you can, and beg reviews. This is the stage I'm in now. I've got web reviews, but I'm trying to get people to take the time and go give Amazon or iPad reviews. They help. Nobody wants to feel like they're the first one taking a chance on what could be a piece of garbage.
Lessons learned so far? The publishing part was fun, and I'd do it again. Marketing, unless you're born to it, is harder than it looks and also a serious ethical dilemma. Every singlel time I try to promote my book in an online way (including now), I worry that I look spammy. Offline is different, you can talk about your book all you want and just seem annoying -- but, you have no way of telling whether you got any traffic out of that, either.
It will be disappointing. The day I published, a former coworker spotted it on Facebook and told me that he'd be picking it up that day. A week later I asked how it was, he said he hadn't gotten it yet. Two weeks later, he still hasn't. Get used to that. Family will back you up, and some friends. But if you think, like I did, that you've got any sort of following that will buy something from you just because they like to read what you've said online? Not so fast. Some will, sure, and I'm grateful to my followers that did. But it hasn't exactly catapulted me into phase 2 of my project yet.
Anyway, hope that added some value. Yes, this is self-promotional, but hopefully not spammy. See the difference? See the ethical dilemma? A link from slashdot, even in a comment, would be good traffic. It's a relevant topic, I have experience to add. Yet I can't help but think just by including my link, people will turn their nose up at it and move on. Who knows, maybe I'm oversensitive to that. Prove me wrong ;).
http://www.hearmysoulspeak.com/ - Wedding Quotations from Shakespeare