Twice-divorced one-time GOP presidential candidate Rudy Giuliani started angry tongues wagging yesterday when he received communion at the pope's mass, which is contrary to church rules. As a divorced Catholic, Giuliani is barred from receiving communion, yet he stepped up to the altar with wife No. 3 at St. Patrick's Cathedral. "He knows better," one miffed Catholic told the New York Daily News. (More Rudy Giuliani stories.)