is it a bipolar or unipolar step motor ? how many phases ?
I use allegro ICs.
For Bipolar driver the 3977 is excellent and very easy to inteface ( but limited to 2.5A ) :?
IMS make 3A driver modules but quite expensive.
293H bridge motor driver & UC1517 stepper controller schematics you can find here "PICmicro Application Design and Hardware Interfacing"
**broken link removed**