As a flash web designer , people often ask about rollovers I use so I created this 5 minute video tutorial showing how to create an animated rollover button in Adobe Flash CS3. This tutorial assumes you have a basic knowledge of flash and understand your way around it. Below is what you will create:
Using this as a base, and the AS, you can apply the principle to make anything play on rollover, and rewind on rollout. Which is how this button/movieclip works.
Flash Animated Rollover Video Tutorial from Acuity Designs on Vimeo.