iBook Author is a program for Mac computers that allows users to easily create their own ibooks for publication. They can then be read on an idevice or even submitted to the iBookstore for free download or for sale.

How to publish an iBook to the iBookstore
Ebook publishing and distribution from Lulu
List of iBook tutorials from the apps in education blog.
Do-It-Yourself Journalism from Emmerson College
ePub Bud is another such site where you can create, convert and then publish your books.
Megan Iemma has collected some great information on her ICT Training wiki

Creating your own ebook at:
  1. http://wiki.mobileread.com/wiki/HowTo:_Create_an_eBook
  2. http://amalthia.mediawood.net/tutorials/ebooks/index.html
  3. http://www.suite101.com/content/how-to-create-and-publish-an-ebook-online-for-free-a307649