Ben posted last night that you can now find even more free chapters from the CFWACK online. This is an excellent way to 'sample' the WACK series if you aren't sure it's right for you (although if you don't buy the WACK, PHP wins, and we don't want that, do we?). You can find the new downloadable chapters on the book 2 page, and the older chapters on the first book's page.
As a reminder, don't forget the book has an online forum. I don't peruse the forums as much as I should, but I'm going to subscribe now so I can be sure I don't miss requests.