Homebrewer's Guide to Watir is a book on Watir. It is not finished. We are working on it.
Book source code is at github.com/watir/watirbook. You can discuss the book at groups.google.com/group/watirbook. HTML version of the book is at watir.github.com/watirbook.
The book is available as PDF, EPUB (iPad, iPhone, iPod) and MOBI (Kindle) file at leanpub.com/watirbook. Suggested price is $9.99, but you can get the book for free! Click Buy the ebook now! button and move the You pay slider to the left hand side until the amount goes down to $0.00. Of course, you can move the slider to the right hand side and pay more for the book. I will not keep the money, all of it goes to Watir project.
More information about the book is available at my blog.
Money that book readers have donated to the Watir project == $105.22 (Updated 2012-12-01. For more stats see stats page.)