We use Clickbank.com as our affiliate program provider. They handle all the billing and check payments. All you have to do is sign up with a free account with them. To sign up all you need to give them is your name, address (where to send your checks) and you will get a username and password with them.  Once you start making sales you can log in to your clickbank account and see how much you have made 24 hours a day.

Sign Up for a FREE Clickbank.com affiliate username and account and start earning 55% on all your sales