jointtech:
So I found this:
Pololu - Dual VNH3SP30 Motor Driver Carrier MD03A
but it seems to use only PWM as input. I'm not comfortable with that yet so would like to stick with analog input. I understand 0-1023.
Any chance we could get your over that fear? We'll be your support group. It'll be like going to an AA meeting 
To control the board you have four main pins. Looking at just the first driver:
1EN : Setting it high powers up the driver and low disables the driver. If you were going to implement a kill switch you would do that here.
1INa / 1INb : When INa is high and INb low, the motor will be set to turn in one direction, and when INa is low and INb is high it will be set to turn the other direction. Setting both high locks the motor and makes it resistant to turning, and setting both low allows the motor to freewheel.
1PWM: when you analogWrite(pwmPin, 0) the motor is stopped, and analogWrite(pwmPin, 255) the motor is full power. Selecting a value between 0 and 255 is a partial power; 64 would be 1/4 power, 128 would be 1/2 power, etc. "pwmPin" is any of the PWM pins on the Arduino: 3, 5, 6, 9, 10 or 11.
Does this seem straightforward?