Thanks, I wonder who is the idiot who downvotes an honest question.
Still, I would pay $9.99 for mobi or epub. PDF is inconvenient for the Kindle and the iPad. Converting with Calibre is a chore, and rarely yields good results.
I find GoodReader excellent for pdfs on the iPad. It's not only a great reader but also allows annotation etc plus makes getting pdfs into and out of your iPad fairly painless
I'm downloading it now. Would like to donate by buying but UK Amazon site lists it as out of stock.