What opensource tools are available for writing in actionscript

Basically I want to make a simple flash application that will take a stream from my webcam and broadcast it over an rtmp server. I know absolutely 0 actionscript at this point. Before I get into learning I need to know what opensource tools are available. I've downloaded mstasc, but I'm having trouble using it. I made a simple script that does no开发者_如何学Gothing but set a variable (var test="test") but this gives me errors (characters 0-3 : parse error Unexpected var)

any advice?

FlashDevelop is a nice open source IDE, but it's Windows only. You've found the Flex SDK haven't you?