Want to make your headphones compatible with Bluetooth? Take a look at Smartbean, the Bluetooth wireless audio receiver should be able to meet your requirements.
The Smartbean is a Bluetooth-enabled wireless receiver designed to offer you an easy way to make your headphones Bluetooth-compatible. The audio receiver measures 1-3/4 x 1-1/4 x 1/3 inches, weights less than an ounce, and as shown in the images, the Smartbean features an ultra compact design, using integrated clip you can easily attach the Bluetooth receiver on your belt, while its 3.5mm audio jack allows you to connect the audio receiver with your favorite headphones in order to pair it with your smartphone for streaming music. Of course, you can also use the wireless receiver to turn your wired speaker into a wireless speaker, apart from that, the integrated microphone and audio controls let you adjust volume, pause and skip tracks, and you can also switch it seamlessly between audio and phone functions.
The Smartbean Bluetooth wireless receiver is priced at $39.99 USD. If you need it, jump to ThinkGeek for more details.