This Hack is based off of two things: 1) the interface spec of the WB controlled PWM audio device, and 2) a Raspberry Pi Hack I was shown that converted the RPi PWM device into an FM transmitter. So, the question is, can a GPIO pin be turned into an FM transmitter that can be heard throughout the house?
The answer is that a GPIO pin can be transformed into an FM transmitter, and that it then and broadcasts nicely--although weakly. If I make every pin a GPIO pin, then I can get perhaps a yard or so from the transmitter device. The hack also has a newer interface, written but not tested, that outputs 4-samples per clock. This should provide a rough 10dB boost to the signal strength since the signa would no longer be undersampled, but I haven't tested the update yet. That and an antenna (I never used any antennas) should be able to provide a nice capability.