Fading in a MC? [n00b]

Hi, I just started messing around with Flash and I am learning some great stuff from the tutorials here but I am having trouble with a few things… right now though my biggest query has to do with fading in a movie clip that I will use to create a similair effect as the one shown in the Snow (http://www.kirupa.com/developer/mx/snow.htm) tutorial.

I changed the snow to a png of a leave (brush from Illustrator) that I converted into an MC. I can get the AS to work fine and the leaves fall great and works perfectly BUT, I can not for the life of me figure out how to fade in the MC/Script that I have at a certain frame.


for (k=0; k<5; k++) {
    duplicateMovieClip(this.brownleaf, "brownleaf"+k, k);

is the code that I am using in the frame to make the duplicate effect.


onClipEvent (load) {
    //specifies the size of the movie stage
    movieWidth = 850;
    movieHeight = 250;
    //variables that will modify the falling snow
    i = 1+Math.random()*2;
    k = -Math.PI+Math.random()*Math.PI;
    //giving each snowflake unique characteristics
    this._xscale = this._yscale=20+Math.random()*70;
    this._alpha = 75+Math.random()*100;
    this._x = -10+Math.random()*movieWidth;
    this._y = -10+Math.random()*movieHeight;
    this._rotation = 0+Math.random() *350;
onClipEvent (enterFrame) {
    //putting it all together
    rad += (k/180)*Math.PI;
    this._x -= Math.cos(rad);
    this._y += i;
    if (this._y>=movieHeight) {
        this._y = -5;
    if ((this._x>=movieWidth) || (this._x<=0)) {
        this._x = -10+Math.random()*movieWidth;
        this._y = -5;

is the code I am using for the MC that is on the stage that does all the work?.. I dunno, anywho, any help would be great! Thank you!

To make it more clear, the effect I am looking for is so that I can have some regular animation of a banner THEN after that is all done, load this so that it fades in and does not just BURST into existance, like it is now.