A menu simple but still not

Hi everyone!

I have been looking around but never found any answers to my question. I have this horizontal menubar with four buttons, when you click on one button it’s color will smoothly fade to another and the previously clicked button will fade to it’s original color which in this case would be white.

I don’t know if you get what I mean but check this out…

http://www.impatrik.com/333.html

That’s the menu and so far it works but the buttons don’t fade as I want and I don’t know how to make them fade and still work properly.

Keep in mind that I’m not good at Actionscrip’s so you’ll have to explain alittle deeper ;/