Conecting Antenas to Arduino (simplified Theremin)

Hi, my project is to conect an antena to the arduino board... if you guys are familiar with the theremin ( Theremin - Wikipedia ) you got the idea that with aproximation to the antena we can control the pitch of sound... well, by conecting only the antena to the arduino I could have a simplified circuit of the theremin and use it to control any parameter of sound or other... hence, a simplified theremin circuit used for generic purposes...

well, that is the idea... now the question is what would be the easier way to concect it to arduino... for now I think it is a matter of getting the antena to work as a regular potenciometer... but then, I'm clueless cause I know nothing bout antenas, electronics, electromagnetism, whatever...

so, is it really the best way to do so? Is there any other procedure or even a similar concept? Is there something plug and play for antenas?

Thanks a bunch folks.
CHEERS!

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1168942948

This is not the thermin idea exactly but works a lot like one. A theramin, as I understand it, uses two radio frequency oscillators, and the audio signal is the beat frequency between them, that one controls by detuning one of the oscillators.

The reference below is a capacitive sensor that operates in low radio frequency

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1171076259

Paul B