SWFObjectでFlashVars　as3

ActionScript3.0

HTML側

var so = new SWFObject("index.swf", "swf-content", "100%", "100%", "9,0,0,0", "#ffffff");
so.addParam("quality", "high");
so.addParam("scale", "noscale");
so.addParam("wmode", "transparent");
so.addParam("align", "top");
so.addParam("loop", "false");
//↓こんな感じで書くと
so.addVariable("country", country);
so.addVariable("area", area);
so.write("flashcontent");

AS側

import flash.display.LoaderInfo;

var params:Object = loaderInfo.parameters;
var area:String = params["area"];
var country:String = params["country"]

で受け取れる。
便利ぃー