I assume your refering to Scanlines well it can depend on the program you are using.
Even though i use Photoshop PSP is very simple to use this method.
Effects > Texture > Blinds (options, width:2 opacity: 7 can variey to your choice)
Another way is simple to go on HBD click PSD's then select the catagory Other, Hope this has helped.
In Photoshop, make a new image that is 3 pixels tall and 1 pixel wide. Use the smallest brush and click at the very top of the image. Ctrl + A to select all, then Edit(I think) then Define pattern. Then go to the one you want to put them on Layer > Layer Options(I think) and go to pattern overlay and use the scanlines. It's a little more complicated, but all you have to do on the rest of your banners is just the stuff from Layer on.