Can anyone tell me which pins on the bottom of this BASIC stamp i connect a pwm wire into in order to connect it to the servo controller underneath it
To be safe you should check the parallax web site…
Essentially all of the pins marked P# are available as inputs or outputs and so are eligible to be used for PWM outputs. I am not sure which servo controller you are using but typically they require a serial out line to the the controller. Again, any of the pins marked P# are available. You then use SEROUT to send the command to the servo controller. Check the documentation that came with your servo controller.
Check this thread for more info.