iOS users can easily take screenshot by just pressing Home+Power/Sleep button, in Android you need to root your phone. But if you are Windows Phone user then there is no support for screenshot in WP7.5.
But Chinese site WPDang originally spotted by WPSauce is reporting that Windows Phone 8 might get key combinations for taking screenshots on WP8. As per reports in WP8 you have to press Windows Key+Camera key to take screenshot.
Well that might be a problem for some as Windows Key might be a touch key or virtual key. Let see what goes on, Do share what you think on this by using comment section below.