1. This is a very simple tutorial that been banded all over the web since the launch of The Matrix: Reloaded and only uses a few filters.

Start off with any size image, but bear in mind that the size of the 'code' will not change, and so it might be worth starting large and scaling down. For the purposes of this tutorial, I'll use a 200x200 canvas.

The first filter to apply is some grain: go Filter >> Texture >> Grain with both the sliders to full, and the type to vertical.

2. The next filter is neon glow - go Filter >> Artistic >> Neon Glow. Set the size to 5 and the brightness to 15, although these settings depend on your taste and the size of the image. The colour doesn't matter at this stage.

3. The next filter is 'glowing edges' - Filter >> Stylize >> Glowing Edges. Set size and smoothness to minimum, and brightness to about 10.

4. Finally, colourize it to the obligatory bright green and put on your desktop, webpages, whatever.