The odd thing is, my boss Brian’s Blackberry does the same thing.
I finally found the reason why:
The cause of this buzzing has to do with GSM’s â€œtime division nature. The ever-knowledgeable Keith Nowak, spokesperson for Nokia, explains it as follows: â€œ[[With GSM]] the RF transmitter is turned on/off at a fast rate, and that â€˜pulsing’ is often picked up by nearby devices that don’t have good RF shielding. In the case of GSM the pulse rate is 217 Hz, which can be easily heard.
When I put my iPhone in the clock radio / iPhone dock that Ginny got me for the holidays, it does the same thing. Luckily the dock isn’t recognized as being 100% iPhone compatible, so the iPhone offers to shut off the radio (go into Airplane mode) whenever I dock it. This eliminates the buzzing (mostly) because the phone isn’t transmitting.