Paul, if you are going to sell your ebook, I recommend to join clickbank to set up an affiliate program (they take care of payment processing as well).
FYI: The commercial success of Tom Venuto's ebook is based on his generous affiliate program (his affiliates earn a commission of 51% per sale!). I think he earns more with his subscription based
Web site that is built to support his readers than with his ebook
.