Oursky Developer Suite
MockUPhone is a free tool that helps you wrap your app screenshots in your favorite mobile devices with multiple colors and orientations. You can wrap iOS screenshots, Android screenshots, Window Phone screenshots and even TV screenshots in over 30 devices by a click.
ShotBot is a iOS screenshot design and submission tool. You can design all iOS screenshots on ShotBot. With one click, you can apply the app screenshots to all locales and sync them to your iTunes Connect account.