12V motor control

Hello.

I am currently working on a project in which i construct a robotic hand. The finger joints are driven by 5V servos, and the wrist is driven by 12V DC motors.

The servos are hobby servos, the Futaba S3003. One of the motors is a power window motor from a LandRover D2. The other is a windshield-wiper motor taken from a Ford F150. What can I say? I love the junkyard.

Anyways, the question is this. I have already hooked up the servos so that they run off the arduino. Their power source is my laptop, which provides power through the USB cable, if I am not mistaken. However, I do not know how to control the 12V DC motors using the arduino.

Does anyone have an example or a circuit which could be used for this application? How should I give the motors their necessary 12V? Is there a way for me to slow down the motors using the arduino, perhaps by using PWM?

Please bear in mind that these are very powerful motors which draw a lot of current. Any help would be greatly appreciated (:

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1236546337

This is a post with almost exactly the same request.

Here are a couple of links that you can check.

You will not be able to run the two DC motors without an external powersupply. And it should probably be a rather large power supply.

Window motors and windshield wiper motors draw a lot of current.

http://ctheds.wordpress.com/2007/10/30/tip-120/

http://itp.nyu.edu/physcomp/Tutorials/HighCurrentLoads