There are two options available, either 3.3V or 5V logic. The VIN is more robust and separate, the connection is better.
If you are looking for a shield that controls two DC motors, then you’re looking in the right place, Based on the L298 H-bridge, the Ardumoto can drive up to 2 amps per channel.
The board takes its power from the same Vin line as the Arduino board, includes blue and yellow LEDs to indicate active direction, and all driver lines are diode protected from back EMF.The first one is the control for a motor attached to OUT ½ which is connected to digital line 12 (direction A) and digital line 3 (PWM A), However, the second motor is attached to OUT ¾ which is connected to digital line 13 (direction B) and digital line 11 (PWM B). Also, the compatibility of it with the screw terminals as well as the connectors is mentioned below in case you wanted to buy those as well.
Product pictures and description are of SparkFun.com