My wife came home the other day with some interesting info. She has a set of Bose QC-2 over the ear headphones for music. On her last return from China, she entered the cockpit per FAA regs while one of the pilots took a potty break and noticed the first officer wearing Bose Headsets. She asked if they were the Bose noise cancelling pilot headsets - I had a borrowed set to evaluate and she knew of them and their cost. The answer was no. They were the Bose noise cancelling music headsets. He explained that a Southwest pilot had developed a microphone arm that would fit into the cord fitting on the QC-2 and QC-15 headsets converting them to Aviation use. United Airlines had recently approved their use on their airplanes. If you have the headsets already, a real good deal to pick up the microphone. If you bought both the headset and the mike arm, still almost half the cost of the aviation Bose.

http://uflymike.com/products/aviation/microphones/microphones.html

I have not tried the microphone, but like the earphones.