OK, this may be confusing to explain. I want to have 3 movie clips inside another container movie clip (the 3 will serve as buttons). When I scroll over one button, I want it to expand at the same time, pushing the other movie clip up or down, depending on where the user scrolls. If i have the three buttons that are each 100px tall for example, and the container mc is say 500. when the user scrolls on the middle button, I would like it to "grow" to 300px, while pushing the 100px button above it to the limit of the container. when the user scrolls to the top button, it would grow to 300px, the middle would shrink back to 100px, and all the buttons would still fit in the container mc. Any suggestions in flash cs5 AS3?
Look into the Tween class for realizing actionscript-based animations. That class is built into Flash. You want to tween the y property for the buttons that move away while tweening the scaleX and scaleY properties of the button that expands. If you Google "AS3 Tween tutorial" you should find something to get you started.
You can get better performance using third party tweening engines such as Tweenlite.