sorry about that. they are also known as the spikes. They cannot be used to power the CIMs (against the rules), but they can be used to power smaller motors like the globe motors. On the spike there is M+ and M- on one side. On the other side there is 12V and GND. The M+ and M- is for the motor leads. the 12V and Gnd is for power to the motor. there is also a three terminal header in the spike. it is rectangular and a pwm cable plugs into that which delivers the signal from the digital I/O sidecar to the spike.
The relay is pretty much just an on/off or forward/off/reverse device. There is no speed control. Determining if you need speed control depends on the application for the motor.
In the WPI libraries there are VIs written for controlling the spike. I think they are under WPI Library-->Actuators-->Relay. By putting those VIs into the code and then clicking the question mark in the right hand corner and hovering over the icon you will get a description of what he inputs and outputs are to the vi.
Here is also more info from NI.
http://decibel.ni.com/content/docs/DOC-3321
hope this helps!