We measured and analyzed the electrical resistivity (ρ), Hall coefficient (RH), Seebeck coefficient (S) and magnetic susceptibility (χ) of γ-phase Na0.6CoO2 and α-phase Na0.9CoO2 crystals prepared by solution growth using NaCl-Na2CO3-B2O3 fluxes. The ρ of α-phase Na0.9CoO2 (ρα) is much higher than that of γ-phase Na0.6CoO2 (ργ), while the magnitude of S of α-phase Na0.9CoO2 (Sα) exceeds that of γ-phase Na0.6CoO2 (Sγ). The origin of these differences is primarily the difference in carrier density. In addition, ρα has a minimum at around 20 K, while ργ exhibits a metallic temperature-dependence throughout the measured temperature range. Since α-phase Na0.9CoO2 exhibits an antiferromagnetic transition at the same temperature 20 K, the increase in ρα at low temperatures implies the carrier localization effect caused by forming a long-range order among magnetic moments in the conductive CoO2 layer.