[vic_]

import mx.utils.Delegate
var keyListener:Object = new Object();
keyListener.onKeyDown = Delegate.create(this,myOnKeyDown);
keyListener.onKeyUp = Delegate.create(this,myOnKeyUp);
Key.addListener(keyListener);

function myOnKeyDown(){
	if( Key.isDown(Key.LEFT) )testIt();
}
function myOnKeyUp(){}

function testIt(){
	trace("test");
}

а так?