Complete button rollout/rollover animation

Hi

I am searching for a tutorial (or, if someone can post here…) that can explain me how to make a complete button rollout/rollover animation.

I want something that can do not only the rollOver animation, but rollOut too. For example, a button that in rollOut becomes bigger, and on rollOver becomes the size that it was before, but with animation on it.

sorry my english

very thanks