The eBook is officially launched today Monday 23rd April 2012. You can read it for free or download here in most eBook formats. To do this, you need to join this website to be able to access that page (terms/privacy). You can then also post your comments on the site.
It will be appearing over the coming weeks in all the main eBook stores, but beware it is possible they may charge for it.
Listen to the author talking about the book below.