If you've ever posted or lurked on a message board before, you probably have come across some users that have images in their post signature, usually touched up in a graphics program, and having their username printed somewhere on the image. You've probably also wanted one of these at some point, too.
Well, here is a short and easy tutorial on how to create a basic image to represent yourself on whatever message board you post on.
First, create a new image in Photoshop, with a width of 350 pixels (standard forum image width size, made popular by user bars), and a height of 85 pixels.
Next, change your foreground color (default: white) to this awesome green (as you read my blog you'll easily spot that my favorite color is this) a4de60.
Select Render > Clouds from the Filters menu (ALT + T) until you get a background you are comfortable with.

Now, to spice up this signature a little bit. Select Pixelate > Mosaic from the Filters menu and leave the cell size at the default (8). Then, select Sharpen > Sharpen from the Filters menu, and repeat this two or three times to your liking. You should have something like this.

It's time to add your username to personalize this image. Choose your text tool, and select a font you think would look good on the signature. I'll choose Impact. Set your font color to white, and your font size to 36 pt, and let's proceed.
Type out your forum username, and position your text in the bottom right. Now, go to your text layer's styles (double click the layer with the layer control window), and add a stroke to the text (1px, 22440f), and also select outer glow, leave the default settings.

Now, I personally like to have a 1px border around the edge of my signature to distinguish it from the rest of the websites layout, usually a black or white line depending on the background color of the forum, and what color my signature used. We'll use a black line here. Create a new layer, and press select all (CTRL + A). Select Stroke from the Edit menu (ALT + E), and create a black 1px stroke around the edge.

Congratulations, you're all finished. Now, just upload this image to your favorite image host (or your own personal webspace) and edit your signature to include this image! (You may have to use BBCode or HTML to post your signature.)