http://www.insideria.com/2008/04/amf3-php-server-objects-to-fle.html

This article first provides summaries of the Flex networking protocols, the server platform alternatives, and Adobe’s AMF 3 (Action Message Format) remote messaging protocol. We then use an example set of client and server code to demonstrate the key concepts necessary to deploy a Flex-based RIA client/server solution. We explain how and why client and server objects—though remote from each other—are unified to the same object structure and content by the use of what is called object relational mapping.