How to make _x movement more fluid?

1

hello,
I would like to ask for help with this problem: I have made xml gallery with thumbnails, following kirupa’s tutorial (http://www.kirupa.com/developer/mx2004/thumbnails.htm). Everything works perfect, but I need to add some more interesting movement on horizontal scroller of thumbnails. For example, thumbnail starts to move quicklier, then they slow down…etc. How can I make it? With some ease, tween class…?
please, if anybody can help , I would apreciate a lot
Thank you very much in advance

here is the code for scroller of thumbnail_mc:

function thumbNailScroller() {
	// thumbnail code! 
	this.createEmptyMovieClip("tscroller", this.getNextHighestDepth());
	scroll_speed =20;
	tscroller.onEnterFrame = function() {
		if ((_ymouse>=thumbnail_mc._y) && (_ymouse<=thumbnail_mc._y+thumbnail_mc._height)) {
			if ((_xmouse>=(hit_right._x-60)) && (thumbnail_mc.hitTest(hit_right))) {
				thumbnail_mc._x -= scroll_speed;
				}
                             else if ((_xmouse<=(hit_left._x+60)) &&    (thumbnail_mc.hitTest(hit_left))) {
				thumbnail_mc._x += scroll_speed;
				}
		} else {
			delete tscroller.onEnterFrame;
		}
	};
}