http://labs.adobe.com/wiki/index.php/Flex:Open_Source
Adobe is announcing plans to open source Flex under the Mozilla Public License (MPL). This includes not only the source to the ActionScript components from the Flex SDK, which have been available in source code form with the SDK since Flex 2 was released, but also includes the Java source code for the ActionScript and MXML compilers, the ActionScript debugger and the core ActionScript libraries from the SDK. The Flex SDK includes all of the components needed to create Flex applications that run in any browser - on Mac OS X, Windows, and Linux and on now on the desktop using “Apollo”.
Developers can use the Flex SDK to freely develop and deploy Flex applications using either Adobe Flex Builder or an IDE of their choice.
[edit]License
The source code for the Flex SDK will be available under the Mozilla Public License (MPL). The MPL will allow full and free access to the source code, allowing developers to download, extend, and contribute to the source code for the Flex compiler and framework classes. The Flex SDK will also be available under a commercial Adobe license. Offering a choice of licenses serves the needs of enterprise Flex customers and partners.
Mozilla Public License FAQ: http://www.mozilla.org/MPL/mpl-faq.html
The annotated Mozilla Public License (Explained in layman’s terms) http://www.mozilla.org/MPL/MPL-1.1-annotated.html
[edit]Schedule
The source code for the Flex framework is already available within the free distribution of the current Flex 2 SDK. By this summer, Adobe plans to put in place most of the infrastructure (public bug database and public daily builds) required to run the Flex SDK as an open source project. We expect to complete the transition to a fully open source project (source code for the compiler, infrastructure for community contributions, etc.) by the end of 2007.
[edit]Currently Supported Platforms
Windows XP, Server 2003, or Windows Vista Professional/Ultimate with Java 1.4 (Sun, IBM, or BEA) or 1.5 (Sun)
Mac OS X 10.4.x, Java 1.5 (as shipped from Apple) on PowerPC and Intel processor
Redhat Enterprise Linux 3 or 4, Suse 10, Java 1.4 (Sun, IBM, or BEA) or 1.5 (Sun)
Solaris 9, 10, Java 1.4 or 1.5 (Sun) Compilers only
[edit]More Information and FAQ
This FAQ will provide all the details and hopefully answer all your questions.
Flex Open Source FAQ
David Wadhwani, VP of Flex Engineering and Ely Greenfield, Flex Architect discuss the Flex Open source announcement with Robert Scoble of PodTech.
[edit]How can I ask more questions?