Opening the Arduino software, browse to "File>Examples>Stepper>stepper_oneRevolution"
This program drives a unipolar or bipolar stepper motor, by attaching the motor to digital pins 8 - 11 of the Arduino. After the sketch is loaded on to the Arduino board, the motor should revolve one revolution clockwise, then one revolution moving counter-clockwise.
The example code is an excellent point to start from, you can certainly make edits to the sketch to suit your needs. The delay is listed in microseconds, so if you want there to be no break between it's revolutions, you can set delay to delay(10). Or if you want it to spin for a long time you can change stepsPerRevolution to equal = (1000000)
How you modify the sketch will depend on what you are trying to accomplish with the motor. Playing with some of the other sketches in the example sketch library will help you develop a greater understanding of how stepper motors are able to communicate with Arduino Boards.