Flash and Open Source

Anders Schneiderman asks: "I'm involved in a project that's planning to create open source toys for educating people around complicated policy questions (e.g., policy on prescription drugs). We'd really like to use Flash as our main language, but we're concerned about the fact that the major Flash development tools cost $500--more than some of the community group folks we want to involve can afford. I took a look at Sourceforge, and while there are plenty of projects that offer ways to create Flash for free, there didn't seem to be any v.1 general development tools. Did I miss something? If you want to build Flash and you don't want to pay $500, how do you do it (aside from copying somebody else's, which as Bill Gates told us is just bad, bad, bad)? And if there aren't any powerful open source tools for it, any thoughts on why?"