These small steppers are a great way to get things moving, especially when positioning and repeatability is a concern.
This is a Bipolar motor.
When using a current limiting driver such as the Easydriver or Big Easydriver, a 12 volt power supply can be used as long as you adjust the current level to 400mA or less. If using a non current limited driver (like a L293D or an H-bridge) you will need to lower your input voltage to keep the motor current below 400mA.