New Document

Since were making a desktop background choose the size you want it to be, 800x600, 1024x768, its really up to you. Now press "D" on your keyboard to reset the foreground and background colors to black and white.

Difference Clouds

Now go to Filter>Render>Difference Clouds. Hit CNTRL+F one time to add more contrast. Now go to Filter>Artistic>Plastic Wrap and use these settings:

Wind

Now apply some wind, do this by going to Filter>Stylize>Wind and use these settings:

Ink Outlines

Apply Ink Outlines, Filter>Brush Strokes>Ink Outlines and use these settings:

Duplicate

Now duplicate the layer (right click the background layer and select duplicate). Now select Screen for the Layer Blending Option, this will add more brightness to the fantasy background.

Clouds

Now make a new layer, then go to Filter>Render>Clouds and set the Layer Blending mode to Screen aswell:

Hue/saturation

Now select your bottom layer Background and press CNTRL+U to activate hue/saturation window, and use these settings:

Hue/Saturation settings

Now select your duplicated later and add these Hue/Saturation settings aswell:

Voila, your image should look similar to mine below: