AS3 Movie Clips on Mouse_Over

Hi All

I need help to create some code that can do the following:

I have a series of flash buttons and the client wants an image associated with each one of the buttons to fade in on the main section of the page upon rollover of the button and then fade out on rollout of the button.

He then wants a new image to fade in when you rollover a different button and fade out on rollover, for all the buttons.

As a greenhorn :top_hat: with AS3 any advice would most gratefully appreciated.