Just to follow up on the FCC frequencies and what not.
72Mhz is set aside for RC aircraft operations; even if you were using this for its intended purpose you would still need to make sure that the frequency was not in use to the best of your ability prior to turning that radio transmitter on. If you were to turn it on near someone else using the same frequency you would cause them to crash and could be responsible for the damages resulting from that crash. These damages could include property, personal injury, death - it isn't insignificant. If you are within 5 miles of an RC flying field or a popular slope soaring spot you should not turn on that radio without first checking to make sure that your frequency is not in use (there are devices that can check for signal on a given channel).
And while these eventualities are probably rare for your intended purpose - you still are taking a great risk whenever you use a 72Mhz, RC Aircraft radio outside of its intended purpose and away from a controller RC Aircraft flying field.
I used to fly my little park flier aircraft at the local ball field until I ran into a guy doing the same thing. I stopped by to talk to him and more specifically to check his frequencies to make sure we weren't using the same one. Turns out - WE WERE! Out of 50 possible frequencies I almost always run into folks who are on the same frequency. I don't understand the math, it always baffles me. In recent years they introduced gear that you could actually change the frequency on it was a little pricey and the frequency challenges only happened once in a while at the field.
Now, with 2.4 Ghz radios it isn't an issue (so far). 2.4 Ghz radios are designed (or are supposed to be) to gracefully degrade as the frequency band becomes crowded. I fly at the Basin in SoCal and it is pretty darned crowded there - especially these days with all the electric aircraft.
75 Mhz is much less risky but still defined for surface (including water) use.
Hugh is correct though, I think you're more interested in some automation than actual control. If you had a 75Mhz radio (which you could get off of ebay very cheaply or I think I have an RX/TX I could send you) you could most likely use the same servos and you wouldn't be risking as much.
check out
Servocity for robotics stuff.