The Sanyo LB1836M is a great low-voltage dual motor driver (dual H-bridge) that we use in our micro dual serial motor controller and original Orangutan robot controllers. The low-voltage operation and relatively high peak current of 1 A make it an attractive option for those wanting to build small motion control systems powered by one or two Li-based cells or a few NiMH cells.  Please find more details at Pololu.com