i have the ardumoto connected to a dc motor and power supply and it works in one direction but not the other!? when the direction pin is high it works, if not it doesnt. am i not understanding something here?! >:(
For one thing you don't want to run a motor directly off the arduino. There is a very good chance that you can damage the arduino.
It would help if you could post i diagram of your setup as well as the code your using.
digimike:
The ardumoto provides 2amps of power, i guess that's enough 
This is a motor shield for Arduino that will control two DC motors. Based on the L298 H-bridge, the Ardumoto can drive up to 2 amps per channel.