OK, in this tutorial, you will learn how to make a cool looking cloud effect in Photoshop CS. OK, lets get started.
Step 1:
Open up Photoshop and make a new 500x00 pixel image (any size will work) with a white background.

Step 2:
Now, go to Filter -> Render -> Clouds. You should get something like this:

Step 3:
Now go to Filters -> Render -> Difference Clouds. You should get something like this:

Step 4:
Now, Press Ctrl + f about 15-20 times. The end result should be something like this:

Step 5:
Now go to Filter -> Render -> Light Effects. Make your setting like the ones below. And you can choose any two colors you like, I like Orange and Red.

You should get something like this:

Step 6:
Now go to Filter -> Blur -> Radial Blur, and use the settings below.

You should get something like this:

Step 7:
Now go to Edit -> Fade Radial Blur. Adjust your setting to the ones below:

You should get something similar to this:

And that’s it. You can use it for whatever you like, wallpaper, sig, avay, etc.