The easiest way to start developing Jangaroo applications is to use Maven. Check out our tutorial to get your first Jangaroo application compiled and running within a few minutes. You don't need to download anything manually (except Java and Maven)!
For those of you who don't like Maven and just want to use the Ant or command line versions of jooc, we promise to provide a ready-to-run binary distribution again soon. Until then, please consider the Jangaroo Tools Wiki page on how to set up a Stand Alone Compiler.
The full source code of Jangaroo is available on github! We created two repositories. One is jangaroo-tools, holding the Jangaroo compiler jooc, the Jangaroo runtime, and development tools like our Maven and IDEA plugins. The second one is jangaroo-libs, which holds some useful ActionScript 3 libraries. Like to make a contribution to Jangaroo? Just fork one of our github repositories, make your changes, and send us a pull request!