The Pololu dual high-power motor drivers are compact carriers for the VNH3SP30 and VNH2SP30 motor driver integrated circuits from ST. The board incorporates most of the components of the typical application diagram on page 8 of the VNH2SP30 datasheet, including pull-up and current-limiting resistors and a FET for reverse battery protection. (The current sense circuit might not be populated on the VNH3SP30 version of the board since only the VNH2SP30 supports current sense.) To keep the number of I/O lines down, the two enable/diagnostic lines on each chip are tied together. All you need to add is a microcontroller or other control circuit to turn the H-Bridges on and off.