Flex Template
Adobe Flex is a software development kit and an IDE for a group of technologies initially released in March of 2004 by Macromedia to support the development and deployment of cross platform, rich Internet applications based on their proprietary Macromedia Flash platform.
In April 2007, Adobe announced plans to open source the Flex 3 SDK. Adobe Flash Player, the runtime on which Flex applications are viewed, and Flex Builder, the IDE used to build Flex applications, remain proprietary and commercial.
At the heart of Flex is the ability to create SWF files that run in Adobe Flash Player. Distill all the features down and really it is a development paradigm that compiles to SWF. It really is that simple but often we make the definition much harder. Just like Flash can create SWF files, so can Flex but the way you develop is completely different.