How To Make Your Gui Smoothly Made Smaller When You Click On It?

Well, I didn't exactly make the question so perfectly clear, so I'll explain it the best I can.

Picture This...

You're on a start menu of a game, it has three buttons (a play, about, and leave), and when you click on one, it slides back to its starting position such as this link here (another question, though, go help the brother.) (http://youtu.be/9feMm4iug7A)

So...

I'm curious on how to do something like that, would I use anyTween functions (for those that don't know this, check it out it's pretty cool (http://wiki.roblox.com/index.php?title=Tweening)), or a moving function that involves Vector3? Thanks for looking at my question, have a good day.

Greek