Open Source Flash Development
OpenLaszlo is an open-source platform that compiles to Flash 7 .swf files. Development is done through a local web server that is included with the compiler. The applications can be compiled on a production server on the fly, or served as static .swf files. The latter is called "SOLO", and is the way that is useful for chumby developers.
FlashDevelop is an open source ActionScript source editor that can be used with the free MTASC ActionScript compiler.