Amazon Flexible Payments Service Part 2, Setup

In order to use Amazon FPS, you will need to create an aws developer account (Amazon Web Services Account) and sign up for Amazon FPS sandbox account.
Follow the steps in the Amazon FPS Getting Started Guide, http://developer.amazonwebservices.com/connect/entry.jspa?externalID=913&categoryID=125
After completing these steps, you should setup you local development environment, and work thru some of sample applications.
I ended up working thru the Java sample applications and rewriting them in C# to get a solid understanding of Amazon FPS.
It is important know what your requirements for you payment application are ahead of time, so that you can pick which features of Amazon FPS you want use. Do you want to retrieve your payment notification from Amazon in a scheduled job or Do you want know instantly when a payment transaction is completed?
If you want to know instantly when a payment transaction is completed and don't want have to deal with creating a scheduled job, then use Amazon's IPN feature (Instant Payment Notification). IPN requires that you setup a Web Service on your web server that Amazon FPS can access to notify you of payments. If you don't want to setup a Web Service for IPN, you will need to go the scheduled job route.