I was making a sig with subzero from mortal combat and wanted a background that was made of ice and this is what i came up with.
1. Make a new .psd file, about 350x150
2. Go to: Filter, Render, Clouds. (make sure you reset the colors before you do this, D )
3. Next do the same as above but do difference clouds. Keep doing it until you get the clouds you want (Ctrl+F) usually you want more white clouds then black.
By now you should have something like this.
4. After you've done that go to: Image, Rotate Canvas, 90 CW
5. Then go to: Filter, Stylize, Wind. make the settings "Wind" and "From the right." Then rotate it back.
6. Then go to: Filter, Sharpen, and Sharpen. Do this at least twice. (you also might want to do it even three times, it all depends on how your sig looks when you do it)
Once you've done that you should have something like this:
If you want you can also go to, Filter, Brush Strokes, Accented Edges, and experiment with that, it kinda gives it a nice shiny effect.
This next thing you don't have to do, but sometimes it's good for making a sig with the render in the middle.
7. Duplicate the layer (Ctrl+J), then select the top layer and press Ctrl+T, then right click on the image and select: Flip Horizontal.
8. Now change the layer mode to Screen or Lighten.
And after that your background should look something like this:
9. Now for some color. Go to the Hue/Saturation (Ctrl+U) and select colorize. Set the Hue to 200 and the Saturation to 45.
And your done. This is how mine came out:
I hope this is easy to understand.
More Tutorials: 
