Yeah, I've got the PWM part nailed down. I will either be using a dedicated controller IC, or mosfets with flyback diodes.
Or are you saying I can just use a lower duty cycle to reduce the torque? That will reduce the speed of my motor under load though. What I really want is a way to prevent the motor from exceeding the current it draws under load, so that if it's stalled there will be insufficient current, and therefore torque.