thanks for the new stepper library in Arduino 008.
i noticed the diagram for "Circuit for Bipolar Stepper Motors" is incorrect, in the Arduino 008 reference: arduino-0008/reference/StepperBipolarCircuit.html
the first diagram on the page, labelled "Two Pins", is just the same as the one in "Circuits for Unipolar Stepper Motors", and won't work with a bipolar motor. i think it's not possible to use ULN2003 for a bipolar motor. for two-pin control you could use an inverter plus h-bridge.
(also noticed that the stepper library reference isn't yet included on the arduino.cc Reference web page.)