office xp administrative install

I would like to ghost an xp pro machine so the whole office can run it.
What do I do ? Lame questions Ill explain.
I install office xp and it asks for the serial. I need to register it so I do so. How will my 70 other machine run ?
I have heard of something called an administrative install? any ideas how I can do this so the office serial gets prompted on other desktops from the ghost image.

Regardless of how it's done, you did get 70 Licenses & serial numbers to cover all the machines it'll run on right?