We follow the evolution and fragmentation of isolated, magnetically-supported, weakly- ionized, self-gravitating molecular clouds in three dimensions. Although the model clouds are supported by the magnetic field, high-density, magnetically-supercritical fragments form due to the drift between the ions and the neutrals, ambipolar diffusion. To follow the evolution of the model clouds, we extended the publicly-available Zeus-MP code to include the effects of nonideal magnetohydrodynamics and have modified several algo- rithms to improve accuracy and convergence. We present the results of a parameter study which varies the ionization fraction, mass-to-flux ratio, and velocity perturbation in the model clouds.
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