One of the most demanding feature that is facility to capture Screenshots which was absent from the core of Windows Phone 7 will be present in the next upgrade that is Windows Phone 8.
It was till now only a rumor that there will be Screenshot capturing facility in Windows Phone 8 but now this is confirmed after this feature was found in action while using Windows Phone 8 emulator. The screenshots so captured gets saved in the screenshot folder in the gallery of Windows Phone 8.
On a actual smartphone a screenshot can be taken by a combination of start + camera keys.