This set includes 8 seamless web backgrounds. The download contains a Photoshop .PAT file and example PSD files.
Tagged: pattern
Use Tilde to create outrageous Illustrator patterns and shapes
If you’re looking for something a little different for a background in Adobe Illustrator, try holding down the Tilde (~) key while dragging out a shape using one of Illustrator’s shape drawing tools such as line, circle, square, etc. Holding the Tilde key forces Illustrator to repeat the shapes in rapid fashion as you drag your mouse around the artboard. 
For fun, I set all the shapes to the same color, then went back and randomly chose a few dozen shapes and made them a different color, then set all shapes to Multiply in the Transparency panel. Try it and you may find yourself busy for an hour or so. Thanks to BittBox for the tip.
How to create seamless patterns in Adobe Illustrator
Veerle has a quick tutorial on how to create seamless patterns in Adobe Illustrator. These patterns make the perfect finishing touch as background elements in your designs, and creating them is simple.