Apparently there is a hidden screenshot utility in the Apple iPhone, and thanks to the work of RipDev it can now be found as all that is need is to edit /var /mobile /Library/ Preferences/ com .apple .springboard.plist. Sreenshots can then be taken via flipping the Mute switch while holding the Home button.
Just how they worked this out we are not sure, but it works, however for those who don’t wish to get down and dirty with the iPhone plist, all you need to do is add http://repository.ripdev.com to your iPhone installer application source list and then install Apple Screenshot Enabler. Job Done!
Source — tuaw