ORIGINAL: Daddysharky
The motor turns much to fast to control so I want to use a PWM to slow it way down. My question is what size PWM do I need. (size =volt and amp rating)
Do you mean what size speed controller do you need?
You may want to start smaller. These places all have good kits and parts:
http://www.pololu.com/
http://www.trossenrobotics.com/
http://www.acroname.com/
Getting back to your first question. The size of the speed controller depends on the voltage and current required for your motors.
-Dave