Image transition, button triggered

[avaloon]

Hi!
I need some actionscript help or other..
What im trying to achieve is an alpha effect with image transitions.
I have some links that I want to make an alpha fade for images when the users passes over the buttons.
The effect that im searching for is like this one:

http://www.kirupa.com/developer/mx/alpha_fade.htm

.
But only, they should be triggered by rollovers not mousemovement. In addition i have some images connected to the buttons. for instance on productslink the product image should be "alpha 100%" and the previous image should animate from 100 to 0 % alpha.
Any ideas??
cheers!¨//Avaloon