Adobe Photoshop (doesn't have to be the latest version)
Step1
1. First open a new document of any size, with a white background. Then go to Filter at the top of the screen, and click Texture, then Grain, and add these numbers into the box that shows.
Intensity: 100 Contrast: 100 Grain Type: Vertical
Step2
2. Now go to Filter again and click on Artistic, and then Neon Glow and add these settings to the box that shows.
Glow size: 5 Glow brightness: 15 Glow color: any shade of green you like
Step3
3. Finally, go to Filter once more, and click on Stylize, then Glowing Edges, and add these settings to the box that shows.
Edge width: 1 Edge brightness: 6 Smoothness: 2
And voila, you have your very own, cool Matrix-like background, for use on your website or your desktop. Hope this article helped.