How to keep movieclip aligned to the right if user resizes window


I’m trying to do a similar effect that this site does:
It’s a full flash site. How do you make sure the scrollbar for example stays on the right hand side of the screen depending on what resolution/size of the browser the user is using. Even if they then resize it, the scrollbar ends up on the right hand side at all times.

Also the content is moved to the center when you resize the width of the screen. At the moment though I’m just interested in how to keep something aligned to the right dynamically.

Would love to know how this is done, any help would be greatly appreciated.