Simple Navbar:
Ima show you how to make a simple clean navigation bar.
1.make a new image 780x100px.Transperant background.
2.Select the Rounded Rectangle Tool and make a shape like this.

3.the right click and make selection.
4.fill the selection with white, then use these Blending Option
Settings:






and that should give you your basic navbar effect.

This blending option alson makes the nav bar look well also:

if you dont know how to make that pattern just do a simple search for
diagnol scan lines.

5.now to make those fancy inset lines you need to create a new
layer.Then you need to make one straight black line 1px wide and one
straight light grey line next to it 1px wide.

FINAL:
this is what my final nav bar looks like...hope you like

(after i tweaked a lil bit dont wanna give it all away)