Step One

First of all, fire up Photoshop, and create a new canvas, mine is going to be 300px*100px, create a new layer, and make a rectangular selection encompassing the entire horizontal area of the canvas, and about 40px high, as shown to the left.
Step Two

Now, fill the selection with a color of your choice (it is irrelevant) and set the fill opacity to 0% Now, double click on the layer, or go layer–layer styles–bevel and emboss to get to the layer styles options.
Step Three

Apply the following layer styles: Bevel and Emboss Style: Inner Bevel Technique: Smooth Depth: 100% Direction?Ǭê?Ǭ•?ǬŠSize: 1 Soften: 0 Angle: 90 Altitude: 55 Highlight Mode: Lighten, Opacity: 80% Shadow: 0% Opacity Gradient Overlay Blend Mode: Normal Opacity: 100% Style: Linear Angle: 90 Scale: 100% Gradient: #4C4E8D –> #34AEE1 Reverse: Checked Stroke Size: 1 Position: Outside Blend Mode: Normal Opacity: 100% Fill Type: Color Color: #253477
Step Four

Click OK, and you should have something *very* similar to that shown to the left.
Conclusion

Well, you are essentially finished, wasn’t that easy! Here is what I came up with using this idea (whilst in a grungy mood :p ) Note that the colors are pretty much irrelevant, you just need to have a dark –> light gradient from top to bottom, then a highlight over the dark part.