Well you make a background image that takes most of the page (down) but like 1px thick. You then using css make it repeat to the side and stop repeating down. Then add a background colour to finished the fade effect
Check out this
code:
<style type="text/css">
body
{
background-color: #000000;
background-image: url('bgdesert.jpg');
background-repeat: repeat-x
}
</style>