Is the wireless part required? If you are just trying to send an on/off type signal, and the distance is sort, I would suggest IR. You can get an IR diode and detector fairly cheap and it would be fairly easy to use with a microcontroller. RF will probably require a module, or specilized IC and more code overhead.
From what you described here's what I would do. Use an IR diode to send a signal to the IR detector, which is hooked up to the microcontroller. The level change would trigger an interupt in the microcontroller to start whatever motion of the motor you desire. If you're trying to do both directions with your motor you'd proabably want to use an H-bridge IC. The H-bridge IC would proabably have an up/down input and PWM input, which you can use to control speed and direction with your micocontroller. Look for a H-bridge IC either with integrated FETs and/or an integrated boost converter. Depending on where you plan to get power, there's a good chance you will need a regulator of some sort. I would get a 12V or 24V wall wart, you can use that for your H-bridge, and then regulate it down to 3.3V-5V for whatever microcontroller you plan to use. For microntrollers, I would suggest arduino, or an Atmel microcontroller.
For fun, you could proabably do this without a microcontroller. You could set up some sort of oscilator and a frequency divider (or another oscilator) to set your PWM value and "duty cycle" for the postive and forward movement. You could use an IR reciever hooked to the enable pin of the H-bridge. When the IR reciever is turned on by the IR diode the H-bridge could be enabled with the PWM value. The slower oscilator hooked to the direction input would set when the motor changes directions.
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