hello everybody i have a project where i should control a car with 2 dc motors connected to the arduino mega from an android application via wifi..anybody can give me some tips circuits or codes. i just bought an arduino mega a wifi shield and i would start to make my circuit. please i need some help. thank u in advance 
You need a H-bridge shield for the motors.
But which one depends on the maximum current (stall current) of the motors.