jremington:
If the motor is to turn in only one direction, a logic level MOSFET and a kickback diode across the motor terminals will do the job.
That's not the case for a brushless motor. A three-wire brushless motor needs an ESC to handle the
phase sensing and commutation. An 8-wire brushless motor needs at least a 3-phase bridge and some
logic to determine commutation (not so daunting as a 3-wire sensor-less motor), but still a cheap ESC
is likely to be a simpler approach in that case too.
Ther Servo library is used to talk to ESCs.