Free on Amazon today only! Happy Father's Day.
I knew of this offer because the Consciously Parenting project is very near and dear to my heart This book is SO good.
In general though, you can find free kindle books easily on the net and facebook. There are many forums dedicated to free and cheap kindle books. I follow several on facebook - including "Free Books for Kindle" and "Pixel of Ink." You just have to weed through the crap. ;)