The multifunction button located on your headphones does a lot more than answer your iPhone or hang it up. You can control the music that’s playing with a surprising amount of functions hidden in that little button. So much so that I hardly ever touch my iPhone to control my iPod any more. Press button once to begin playing music. Use the button’s volume controls to increase or decrease playback volume. Press button once to…"How to Use Your Headphones to Control Your iPhone Audio"