For this tutorial you are going to need:

20/20
Filter Factory M

This is the picture I am going to use for this very
simple tutorial :-)

Open this picture in PSP. Then go to effects, 
plug-in filters, filter factory M, rippler.......

Use these settings:

Your image should look something like this:

Save this picture and open it in 20/20. In 20/20 you go to image,
tile effect.
You can always apply the muted background option in 20/20 if
you want.....

Voila, another background is finished :-)