Horizontal scrolling gallery problems

I have a simple question that I cannot seem to find a simple (keyword) answer to. I am setting up a horizontal thumbnail gallery in which I want to move right or left when the mouse is over it (only when the mouse is over it).

My problem in searching is this: I don’t need it to be infinite (I have the thumbs set up in an mc and a mask to specify what can be seen). I don’t want it to move until the mouse rolls over the mc and I just need it to move either right or left until it reaches the end. All my searching has uncovered is seemingly more “flashy” (excuse the pun) versions of this simple idea. Just a simple actionscript to make the mc move right or left would be FANTASTIC. Actionscript is NOT my strong side.

Thanks beforehand.

Jess