[Jewelz]

addEventListener(KeyboardEvent.KEY_DOWN, startMove);
addEventListener(KeyboardEvent.KEY_UP, stopMove);
 
function startMove (e:KeyboardEvent):void
{ 
  addEventListener(Event.ENTER_FRAME, move);
}
 
function stopMove (e:KeyboardEvent):void
{
   removeEventListener(Event.ENTER_FRAME, move);
}
 
//UPD:
 
function move (e:Event):void
{
    object.x --;
}