RepRaps, Makerbots, Printrbots, String-drawing robots... you see these devices all over the open-source hardware world these days, and yo know what they have in common? Stepper motors. They're relatively cheap, precise, powerful, and ... a son-f-a-gun to make move properly. But since big IC companies also see how useful they are, there's a large variety of ways to connect and power the 4, 6, & 8 wires that are needed to make a stepper motor move. And Pololu does a great job of making boards that use these chips!
Proven Allegro A4988 Stepper Motor IC Simple and proven "Step" and "Direction" control method High-temperature thermal shutdown, under-voltage lockout, and crossover current protection Built-in short protection 8-35VDC input (1.0A continuous current per phase (no heatsink nor airflow cooling (2.0A continuous current per phase (with adequate heat-sinking/cooling 3-5.5V logic input full, 1/2, 1/4, 1/8, and 1/16 microstepping modes Unsoldered (but included) header pins