This tutorial shows how to make a transparent text panel with a drop shadow over an image or Photo.
Open an image or photo to use for a background.
Select the Rectangular marquee tool. Make a selection on the image, this will be where the panel will go.
Hold down the Ctrl. Key (Mac: Command key) and click on the new layer button on the layers pallet. This makes an Adjustment Layer. Next to where it says "Type", select "Levels" from the menu. Click ok. The Levels adjustment will determine the brightness of the panel and how the background shows through. The first adjustment should be moving the bottom black arrow. Slide it to the right a touch but not all the way. Click ok when done.
Back on the Layers Pallet, make sure the layer that says "Levels" is active. Now go to Layers>Effects>Drop Shadow. Click ok when you like the shadow. Add text and you are finished.