yes they do; i'm not sure about other brands but i use an i-tech clip stereo headset that acts as handsfree and wireless headphones. it has 2 earphones; the other can be unplugged when you want to use it simply as handsfree.
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?