Click on “Rounded Rectangle Tool” and make a rounded rectangle as shown

Right click on its layer and click on [ Rasterize Layer ].

Result:

Press Ctrl + T and right click and click Warp

Result:

click on [ Rectangular Marquee Tool (M) ] and make a selection as shown.

Press Delete key to remove selected area

Make its Style
Double click the layer or go to Layers->Blending options and apply settings as shown.

How make this gradient:

Result:

hold down Ctrl than click on its layer to make selection of it.

Go to Background Layer and press Ctrl + T.

Right click and choose warp.

Result:

Press Ctrl + T and right click then click Skew

Result:

Now make a new layer and use [ Gradient Tool (G) ] to make a gradient as shown below.

Here is final result :

Change its opacity to 80%.

You can add your text easily! and also use this button for making a navigation bar.

Final Result:

Via: Stylish Web 2.0 Navigation Buttons