::Step 1::

First take a clear background, wich makes a clear vision of the transparency later on... I took this.

::Step 2::

Create a new layer and pick the rounded rectangle tool. Make a white rectangle in the middle of the picture.

::Stap 3::

Now go to layer styles and copy these settings.

Blending options
Drop Shadow
Inner Shadow
Inner glow
Bevel and Emboss
Stroke

Now you have something like this.

::Optional step::

IF YOU WANT you can add a color overlay too. Pick multiply, overlay or lighten and play with the opacity.