Spiro T. Agnew, who resigned the vice presidency 15 years ago, was in good condition after he fell from a bicycle and broke a hip. Agnew, 70, who lives near Eisenhower Medical Center in Rancho Mirage, Calif., was admitted to the hospital Sunday after being taken there by ambulance, a hospital spokesman said. Agnew resigned the vice presidency in 1973 just before pleading no contest to federal charges of tax evasion on $29,500 he received in 1967 while governor of Maryland. Agnew, who was vice president for nearly five years under Richard Nixon, had been elected governor in 1966. The only other vice president to resign from office was John C. Calhoun in 1832.