Zymic

Make a new document and make a new layer. Grab the Rectangular Marquee Tool and make a selection similar to the size below.

Do not deselect just yet, change your foreground and background colours to the ones below (#6478A0 & #84B9F5):

With the selection still in place grab the Gradient Tool and drag from bottom upwards in the selection. Doing this will give you the below gradient:

We now need to add the glossy shine to it, this in fact, is very simple to do. Grab the Rectangular Marquee Tool again and make a selection the full width but half the height of the bar.

Now make a new layer and fill the selection in with the colour white. Change the blending mode to "Soft Light" and the layers opacity to 36%. Press ctrl+D to deselect.

You may be thinking, what's the point in this tutorial.. if I want to create this effect for my forum i'll use the default theme which is identical! Well using this effect doesn't necessary have to be for a forum, you can incorporate it into lots of other interfaces or what ever your wanting to make. Below is an example content box you could make: