The headphone control adapter is VoiceOver compatible with 5th generation iPod nano and the 3rd generation iPod shuffle. It has volume and track control (play, pause, stop, forward, back) for all iPods that use the headphone jack for transport controls. The control adapter can also be used in cars with an Aux Input jack so you can hear the artist and song titles while keeping your eyes on the road.
Apple thought they could force you to use their headphones. Good thing someone thought otherwise. The headphone control adapter will be available soon for $19.99.