What happens if Rumsfeld is fired/resigns?

[pelastration]

So, about my actual question:
Pelastration, you said Wolfowitz would become acting secretary, would Bush later appoint a new Secretary of Defense and Wolfowitz become deputy again, or would Wolfowitz become Secretary of Defense and a new deputy be chosen?

I realize it's unlikely that Bush will dump Rumsfeld, I'm just curious about the process that would happen if he did.

I suggest you take a look at: http://www.reagan.utexas.edu/resource/speeches/1985/51485b.htm

I don't know if it's still acurate. It starts with:

Executive Order 12514 -- Prescribing the Order of Succession of Officers To Act as Secretary of Defense, Secretary of the Army, Secretary of the Navy, and Secretary of the Air Force

May 14, 1985
By the authority vested in me as President by the Constitution and laws of the United States of America, including section 3347 of title 5, United States Code, it is hereby ordered as follows:

Part I. Succession to the Position of Secretary of Defense.

In the event of the death, disability, or absence of the Secretary of Defense, the incumbents in the Department of Defense positions listed below shall succeed to the position of, and act as, Secretary of Defense in the order indicated:

1. Deputy Secretary of Defense.

2. Secretary of the Army.

3. Secretary of the Navy.

4. Secretary of the Air Force.

5. Under Secretary of Defense for Policy.

6. Under Secretary of Defense for Research and Engineering.