A small vehicle I am playing with was to be driven by stepper motors. I had two Unipolar motors available which seemed just about right. Similar motors can be found in disk drives.
Unipolar motors have four coils and are likely to have five or six wires attached.
If there are five wires then one is common. If there are six wires then you have the pairs of coils identified for you. The connections look like one of these diagrams. A quick poke around with a multimeter set to measure resistance will soon allow you to identify the connections. For now you can label the coils as A, B, C, and D as in the diagram, don't worry about which is actually which just yet.