I finally managed to submit my first article for WSO2 Oxygen Tank. It is about how to do online shopping with Amazon Web Services using Web Service Framework for PHP.
There I'm demonstrating how to write a simple client library to access Amazon Web Services and how to use that library to write your own application to do online shopping with Amazon.com
There I attached the Client library code and two sample applications, one very simple php command line application and the other much improved web application. Hope this will be useful to people who are interested in working with WSF/PHP.