Menu help pls -dynamic text

How do i achieve this affect:
http://www.silverleaf.de/silverleaf/silverleafv2.htm
(if you click on the top button, then it changes its name)

I have a button.
I put a dynamic text field onto it.
I want the default text to be CLICKME
Then after it has been clicked it moves ( i know how to do this already)

So i want that after it has been clicked then it says HOME
so when you click it, it moves back to original position
and changes back to say CLICKME

Can someone PLEASE PLEASE help me out, this must be actionscript…and i dont know actionscript…so any code, or FLA would be great?