Arduino Micro + Lego
After a bit of research, I finially have two fully working sketches. One is for autonomous mode using dual ultrasonic SR04 modules and the motors are running straight from a L293D and 6 volts worth of double A's. I did manage to get speed control, but not really sure how it is working since the pinout is not addressed as a voltage and it doesn not appear to be PWM...but it is good enough to match speed on both of the old spybotic motors.
The second sketch is bluetooth through the BT2s module and BlueTerm using u/d/l/r for direction commands.
My next task will be to integrate the two sketches so it will run either mode.