We're great fans of the MrHobbyelectronics' YouTube channel, and in the latest update they show us how easy it is to use the Freetronics HBRIDGE Motor shield for Arduino by demonstrating a neat Arduino-based tank robot.
With the addition of an ultrasonic distance sensor to avoid collisions, and an infra-red sensor at the front bumper to detect a line - the robot can follow lines and also avoid objects in the way. You can see this in action through the following video:
If you're looking into starting with Arduino and robotics, such as controlling a stepper motor (or DC motors) from your Arduino or compatible, check out our HBRIDGE: DC/stepper motor shield.
Based around the powerful Allegro A4954 H-bridge driver IC you can control two DC motors with complete ease, or one bipolar stepper motor. With connections for external power management, a complete beginners' guide and documentation - motor control couldn't be any easier. For more information and to order, visit the HBRIDGE: page.