The nature of the paramagnetic-insulator-to-ferromagnetic-metal transition and the associated colossal magnetoresistance (CMR) in doped manganites is re-investigated on the basis of the double-exchange model by using a Monte Carlo technique. We calculate the temperature dependence of the magnetic susceptibility and resistivity by taking account of the magnetic fluctuation together with the long-range hopping correlation. The results show Curie-Weiss behaviour of the susceptibility, consistent with a sharp peak in the resistivity near the Curie temperature T_c. The estimated value of T_c and the magnitude of the CMR in the magnetic field are in good agreement with experiments. Our results clearly demonstrate the importance of the magnetic fluctuation and the long-range hopping correlation in the CMR manganites.