var effectTxt:String = _root.effect.text; //gets your text
_root.effect.text = "";
var startEff:Number = 1;
_root.onEnterFrame = function() { //adds a letter on each frame
if (effectTxt.length>=startEff) {
_root.effect.text = effectTxt.substr(0, startEff);
startEff++;
}
else {
delete _root.onEnterFrame} //stops code when effect is finished
};