That is the current rumor currently circulating. It’s according to NBC:

I still have reservations about Giuliani running any agency within the government. But given the financial ties he has around the world with countries that have less than stellar reputations, this might be a better for him.

Righ now, it is merely a rumor. But it is one that could lend some weight to the possibility of Mitt Romney being considered for Secretary of State.