Hi Everyone, Mark from Smashwords here. We're one of several aggregators serving the iBookstore.
Here's our handy checklist on iPad ebook publishing via Smashwords:
http://www.smashwords.com/about/howto_publish_ipadebooks
Quick condensed summary:
1. Sign up for a free account (everything is free at Smashwords)
2.
IMPORTANT Study and implement the Smashwords Style Guide at
https://www.smashwords.com/books/view/52 to learn how to format your book for Smashwords. If you carefully follow it, your book can make it to Apple faster. If you don't follow it, you'll only frustrate yourself and delay distribution. If you don't have the time or patience to follow it, click the Smashwords customer service link (top of any SW page) and request "Mark's List," my list of Smashwords authors who provide low cost formatting and cover design for their fellow authors. You'll upload your book to Smashwords as a Microsoft Word .doc file. If you don't have MS Word, the free Open Office will work (though Word is best).
3. When you upload the book file, you'll also upload a separate front cover image. The image should be a vertical rectangle shape (our requirement, not Apple's) and at least 600pixels tall (Apple's requirement). No greyscale images.
4. Attach an ISBN to your book via our ISBN Manager. Apple requires ISBNs. If you don't have one, we can provide you one for free via our ISBN Manager (in your Smashwords Dashboard). Your ebook ISBN should be different than your print book ISBN.
5. Opt in to our Apple channel.
6. We pay you 60% of the list price you set, paid quarterly. We also publish free books at no charge to you.
7. After you upload, we review your book for inclusion in our Premium Catalog, which is what we ship to Apple and other major retailers and mobile platforms. we evaluate for good formatting and complete metadata. See
http://smashwords.com/distribution for how/where we distribute
For a comprehensive FAQ, see
http://www.smashwords.com/about/supportfaq
Final note: To publish at Smashwords, you need to be the original author or exclusive electronic publisher or distributor. No public domain works unless you're the author. The book must represent a complete, standalone story or collection of short stories. No works-in-progress or partial books. And then there's the common sense stuff - no erotica that involves children, no books that advocate illegal activities, no hate speech, etc. Our TOS is here:
https://www.smashwords.com/about/tos