Fade in letter by letter...

embed a font, assign it a linkage id (eg, ArialRegID) and you can use:

import mx.transitions.Tween;

import mx.transitions.easing.None;

var tfor:TextFormat = new TextFormat();

tfor.color = 0xff0000;

tfor.size = 14;

tfor.font = "ArialRegID";

var parent_mc:MovieClip = this.createEmptyMovieClip("parent_mc",this.getNextHighestDepth());

fadeTextF("this is text to fade",parent_mc,tfor,1,.1,5,20,10);  // do not change any code except in this line where you assign the parameters for your fade and the textformat you want applied to your text.

function fadeTextF(s:String,mc:MovieClip,tfor:TextFormat,fadeRate:Number,displayRate:Number,letterSpacing:Number,x:Number,y:Number):Void{

    var prevX:Number = 0;

    var a:Array = s.split("");

    for(var i:Number=0;i<a.length;i++){

        var tf:TextField = mc.createTextField("tf_"+i,i,prevX,y,10,10);

        tf.embedFonts = true;

        tf.autoSize = "left";

        tf.multiline = false;

        tf.text = a;

        tf.setTextFormat(tfor);

        tf._alpha = 0;

        prevX+=tf._width+letterSpacing;

        setTimeout(function(tf:TextField){new Tween(tf, "_alpha", None.easeNone, 0, 100, fadeRate, true);},displayRate*i*1000,tf);

    }

    mc._x = x;

    mc._y = y;

}

p.s. please mark helpful/correct responses.