Does the president need a passport?
Do you mean do Clinton or Bush have one or do they need one when they visit a foreign country?
I imagine that each man has one, but a head of state doesn’t have to show one. I’m pretty sure that would violate diplomatic protocol. Normally a head of state is greeted by a head of state or some other suitable representative when s/he vistits a country. There’s no customs or immigration official checking the President’s papers.