Why not build it in pure AS3 instead of a .fla? This means people who don't have access to the Flash IDE or Flex Builder can't do diddly squat with it.<p>Pure AS3 would enable use of the free Flex SDK instead.
I take it you need something that can be embedded in a webpage. Otherwise, there's always: <a href="http://projects.gnome.org/cheese" rel="nofollow">http://projects.gnome.org/cheese</a>