MockUPhone is a free tool that helps developers, designers, project managers and consultants wrap app screenshots in different mobile devices. Developers and designer can use the provided PNG files to make mobile screenshots and mockups for mobile application websites or advertisements. While project managers and consultants can embed the screenshots in keynote for their client projects. MockUPhone right now supports iPhone mockup, iPad mockup, Android mockup and TV mockup.
If you want to create screenshots for App Store submission , you can also check out one of our developer suite - ShotBot (http://shotbot.io/). ShotBot is screenshots makers for iOS platform. It helps you wrap screenshots and implements screenshot device art effortlessly.