A few notes i made whilst investigating.
You will need ISBNs for all titles you intend to distribute
How to publish a book to the Kindle:
How to publish to iBooks
For Mac users, the choice of tools is small, but good. First, there’s the free Calibre ebook management tool.
For formatting, you’ll need a full-powered EPUB editor. Sigil is a free open-source editor.
Next, there’s the inexpensive (US$49.99 for a single license) iStudio Publisher.
If you happen to be an Adobe InDesign CS4 (US$699) user, you’re in luck. publishing supports EPUB and will also work on both iBooks and the Kindle