Controlling 2 phase step motor

I was wondering the required electronics to control a 2-phase stepping motor, model ph265-05-a6 by Vexta, 1.4V - 3.8A. It has two connections, one marked as THDM -m1op by winchester electronics and the other is a four wire connection. I have no idea what I need or how to control it as I have just used the motor that came in the standard Arduino package. However, I'd like to work on projects with a little more power.

Any help is appreciated.

In principle standard bipolar stepper drivers will work, but you won't find one on the hobby market that can handle the rated current of 3.8 amps/phase. That motor is intended for use with an industrial chopper driver, for fast, high torque action. The Gecko is not expensive compared to some others: http://www.geckodrive.com/geckodrive-step-motor-drives.html

Or, look for a motor that you can run with less expensive drivers like those from Pololu (who have a reasonable selection): http://www.pololu.com/category/120/stepper-motor-drivers