A highly request feature was unveiled by Joe Belfiore yesterday at the Nokia and Microsoft press conference - the ability to take screenshots in Windows Phone 8. Pressing the start and power buttons simultaneously will take a shot of the screen and place it in a camera roll folder.
The long awaited functionality has been continuously requested by Windows Phone owners, particularly bloggers and reviewers who could make use of an in-app screenshot feature. While there are a variety of homebrew solutions available, it's more effective for marketing the platform if a desired feature found in other smartphones is now sported in Windows Phone.
Comparison website Recombu managed to get some screenshot action on film with a demonstration.