In this tutorial, I will create an effect like the one in the header of the MSNBC.com website. This effect is a reader's-request tutorial.
If you have an effect you want to know how to achieve, just let us know in the comments and we will try to write a tutorial about it.
Create a new document. Double-click on the background layer to open the Layer Styles. Select the Gradient Overlay and use black and a dark blue for the colors. Select Radial for the Gradient Style.
Create a new layer and fill it with black.
First select black for the foreground color and a medium grey for the background color. Go to Filters>Render>Fibers. Set 36 for the Variance and 1 for the Strength.
Go to Filters>Blur>Motion Blur. I set the distance to 999, the maximum value, but feel free to test another value. For the angle use 90Âº.
Double-click on the blurry layer in order to open the Layer Styles dialog box. Select Gradient Overlay and Overlay for the Blend Mode. For the colors, use the rainbow colors: start with violet, blue, green, yellow, and red. I think those are the colors :)
Using the Lasso Tool (L), set the Feather option to 30px and create a random selection like I did. After that go to Layer>Layer Mask>Reveal Selection.
This is a very simple but cool effect. You can use it for website headers, CD covers, and wherever you want. I've just created a beautiful wallpaper for my blog. Again, there are lots of ways to achieve the same result, maybe using other filters and settings. It's all about playing with the tool. Additionally, if you are using the CS3 version of Photoshop, you can use the Smart Filters to test different values and see the effects without worrying about losing the previous version.