This document provides an overview of how Flex and PHP can work together to build rich internet applications (RIAs). Flex is a framework for building RIAs that provides features like advanced user interfaces, data visualization, real-time collaboration and more. PHP can be used to expose data and business logic through web services that Flex applications can call. Examples shown include using PHP with AMF to connect Flex UIs to databases, building real-time applications with sockets, and leveraging PHP for collaboration features.