A new app has been released in App Store which will allow you to take pictures on iPhone using the middle button of the Earphone. The name of this app is Earphone Camera. After installing this app on your iPhone you can use your Earphone to take pictures and take videos just like a Wired Remote. The Middle button of the Earphone can replace the iPhone Home button. Simply connect the Earphone to your iPhone then launch this app. Now simply use the Middle button of the Earphone to take a picture.
Earphone Camera app is compatible with iPhone, iPod touch, and iPad. It requires iOS 4.0 or higher. This app is available through the App Store in the Photography category. It costs $0.99 USD. You can download and get more information about Earphone Camera app from here [iTunes Link].