Persistent photoconductivity has been used to probe the metal-insulator transition in the diluted magnetic semiconductor Cd1-xMnnTe : In. We have measured the d.c. conductivity of Cd0.92Mn0.08Te : In with tunable photogenerated carrier concentration, from the insulating phase up to ∼ 1.2nc in the same sample. In the insulating phase, Efros-Shklovskii variable range hopping conduction is observed. In the metallic phase the temperature dependence of the conductivity is adequately described by quantum corrections to the zero-temperature conductivity due to the effects of electron-electron interaction and weak localization. In the critical region the scaling theory of electron localization has been applied. We observe a critical carrier concentration ∼ 2.3 × 1017 cm-3, and a critical conductivity exponent close to one.