Animating the .y value of the stage

If you go to http://twocreate.co.uk/flash.html and press contact, you´ll see a very neat way of diplaying the contact information.

My question is, how do you go about to change, or move the current stage down like it´s done on that site.
Note that it doesn´t matter what is currently displayed when you click on contact.

Any ideas on that?

Thanks in advance

/Rundevo