The LM567 tone decoder, which I'm considering using in this project is a Voltage Controlled Oscillator (VCO).  As such, to have a paired transmitter and receiver you either have to have a pot to tune each side, or regulate the supply voltage.

For ease of use I want to avoid having to tune the circuits.  I also don't want to limit applications by requiring both the receiving device and transmitting device to be running at the same voltage.  So I'm planning on using a voltage regulator that can supply all of the wireless wires with a fixed voltage, regardless of the device they are being used in.