1. Begin with a new file, 400×50, with #707070 as your background color, then create a new layer in layers palette.

2. Now take the Polygonal Lasso Tool and draw a shape as the image below shows. Hold down Shift to get straight lines.

3. Go to Layer>New Fill Layer>Gradient, now click OK, then look at the images below and do what they shows.

4. Now go to Layer>Layer Style>Stroke and set the Size to 1px and change the color to black #000000. And now should it look something like this.

5. Now hold down Ctrl and click on the Layer mask thumbnail to get a selection, then create a new layer.

6. Go to Edit>Stroke and set the Width to 1px, Color white #FFFFFF and set the Location to Center, click OK, then add some text to the Navigation Bar and you are done!

This is what I came up with.