Flex is a powerful, open source application framework that allows you to build mobile applications for iOS, Android, and BlackBerry Tablet OS devices, as well as traditional applications for browsers and desktops using the same programming model, tool, and codebase. You can build Flex applications using Adobe Flash Builder which is an enterprise-class Eclipse based IDE. This tutorial will provide you an in-depth understanding on Flex concepts needed to get a web and mobile application up and running.