In this tutorial, we will make a nice wallpaper.
1. Start a new image, 640x480. Or, if you want, you can make it your wallpaper size.
2. Using white as your foreground color, and black as your background color, do Filter > Texture > Grain ( Intensity - 100, Contrast - 100, Grain Type - Vertical ).
3. Filter > Sketch > Halftone Pattern ( Size - 1, Contrast - 1, Pattern Type - Dot ).
4. Filter > Blur > Radial Blur ( Amount - 25, Blur Method - Zoom, Quality - Best ).
5. Image > Adjustments > Hue/Saturation ( Colorize it to your liking ).
6. Copy layer.
7. Set the new layer's blending mode to Overlay.
8. Now, this last step, I did, but it still looks good without it. Filter > Distort > Pinch ( Amount - 100 ).
And my final, cropped, result.

Creator B)