1) Write the book (3 months to 10 years, depending on the book and author)
2) Rewrite the book (because the first draft is never good, believe me)
3) Find an eEditor.
4) Author (or agent, if represented) negotiates deal with the publisher. With print publishers, authors keep 5% of paperback and 10% of hardcover per book sold, but in ePublication, authors can get anywhere from 35 - 85% of sales price, the distributor (Amazon(Kindle), Barnes and Noble(Nook), Apple(eBook), etc. takes a cut with the ePublication company taking a cut too.
5) eEditor edits the book - 2 - 3 weeks depending on the word count of the book. More if it's huge.
6) Publisher obtains waivers, and licensing agreements for all photographs and art -- this can take 2 to 3 months because lawyers are slow and never pick up their phones.
7) Final pages are sent to be digitized (takes about 2 weeks)
8) Publisher negotiates fee for book with the distributors, plus the marketing campaign is planned and negotiated with distributors (2 to 3 more weeks)
9) Book launch date picked (holiday season? summer release?) and viola, it's done.
All in all, if my counting serves me correct, from the time the book is given to the eEditor, it takes approximately four months for it to reach the consumer, not bad considering it takes a year for print. an eBook can also be available on Print on Demand with Amazon, so while your book can be available on eReaders, it can also be purchased on paper. This deal should be negotiated by the ePublisher.
Hope this helps!
It'll all be out of date by next month...Believe me.