Lately i have been really working on how to get a dc motor running without shield if anyone knows how to do this please do inform me. I have looked everywhere and have not found a successful outcome. =( 
If you have downloaded the Arduino IDE there is an example of how to run a motor.
Open the IDE, go to File, Examples, 10.Starter Kit, p09_MotorizedPinwheel.
This will get you started on how to control a small DC motor.
Hope that helped.
If you only want the motor to spin one direction the answer is a transistor and FET,
plus free-wheel diode. Think of the motor as like a relay, but more interesting (since
you can PWM it).