Step one:

First create the case, select the round rectangle tool then set the radius to 80 px. In a new layer create a large #484848 rectangle.

Add the following layer-styles: Inner Glow, Gradient Overlay, Pattern Overlay, Stroke.

Step two:

Select the round rectangle tooland set the radius to 20 px. In a new layer create part of the scene by adding a #686868 rectangle in the middle of the case.

Cut out the top edge so it's flat instead of having round edges.

Add the following layer-styles: Inner Sahdow, Inner Glow, Stroke.