1.)Ok first make a new document. Fill the background with black and then make a new layer.

2.)Using your star brushes smack some stars around on the canvas. I know that's not very descriptive but use your own judgement. One thing you can do to give them depth is every time you use a star brush make it on a new layer. Then try changing the opacity and lightness/darkness of those layers to different values. That way you can give it some depth and variety.

3.) Now it's time for the clouds. Chose the default photoshop brush that looks sort of like a cloud. (I've got them circled in the screenshot.) Choose the size based on the size of your document. I'm going to use a small one but I used the size 39 I think for my wallpaper.

4.) This is the part that requires Photoshop 7. I don't know how 6 handles random brushes so I can't help you if you only have 6. In the right hand corner of Photoshop you will see the "File Browser" and the "Brushes" tabs. Click the Brushes one and then click on "Scattering" and "Shape Dynamics" like I have in the screehshot. you can change those settings depending on your needs. Scattering more will make the color less dense, and changing the shape dynamics will change the size of the brush which doesn't really help a lot now but we will use it later for the feathers.

5.) Now just drag the cloud brush around on the canvas. Again use your own judgment. Don't fill the whole screen with just one cloud just do a part. You will notice it looks a little harsh and not much like clouds? Well duplicate the layer and then on the under layer go to Filter>Blue>Guassian Blur and blur it. It looks better now doesn't it?

6.) Keep on doing that but make each new cloud on a different layer. Guassian Blur some of them more then others. As you can see in the picture I have one that I really blurred in the background so it looks like just a white streak. (Tip: if you want your clouds fluffy make the increase the ammount that they scatter.)

7.) Now comes the interesting part. Copy the layer of one of your clouds. While on that layer hit Ctrl + U and the Hue/Saturation window will come up. Click the "Colorize" box and move the levels around until you have a color you like. Now got to Filter>Blur> Radial Blur. Change it to a zoom blur and make it blur 100%. Now move the Blur Center so it is over where your colored cloud is in your picture. You can kind of see what I mean in the screenshot.

8.) Most likely you will have to zoom blur it more then once. I did it 3 times. But then I had only a faint color left so I duplicated the layer. Now you can see my white cloud with the zoomed blue cloud behind it giving it that glow.

9.) Repeat steps 7 & 8 for each of your clouds. Here is what I ended up with.

10.) Now change to the feature brush. Remember to change the Shape Dynamics a lot like how we scattered the cloud brush. My affiliate TekuTeku has a nice tutorial about doing this sort of thing if you are confused. Just slap the feather brush around until you get something you like. Mixing it in between the clouds and stars layers gives it depth. Here is what I got.

10.) Ta Da! I added Dark and some text and it's done. If you have any questions feel free to email me.