Make a new image: 150x150 dot White for background
Filter>Noise>Add Noise. Amount 60, dot Gaussian and check Monochromatic. Click ok.
Stylize>Emboss. Angle: 125 (for an inner emboss, enter –55), Height 1, Amount 80. Click ok.
Filter>Other>Offset. Horizontal: 75 and Vertical: 75. Click ok.
To color this texture, go to Image>Adjust>Hue/Saturation. Check the "Colorize" box. Lightness: -20. Saturation: 25. Now move the top Hue fader until you find a nice color.
Saving the Image
Go to File>Save for Web and compress as a GIF file. Your image is now ready to be placed on your web page background.
Testing out
the pattern
This is something you might
want to consider after you have finished the pattern.
1) After you have covered the seams, Select the image: Select>All. Now go to Edit>Define Pattern.
2) Open a new image, make this one much larger like around 500x500 Pixels.
3) Next, to see what the pattern looks like, go to Edit>Fill. Select "Pattern" where it says "Use" and click ok. This should fill the image with the pattern.