Pixelmeasure Background Template!

<body> Source Code:
<body bgcolor="#ffffff" topmargin="0" marginheight="0" leftmargin="0" rightmargin="0" marginwidth="0" background="/images/margins.gif">

Using CSS (the right way to do it!) the declaration should be:
body { margin: 0px; background: url(/images/margins.gif) fixed top left no-repeat white; }

margins.gif is the background image. This template can be very, very helpful for validating CSS layout, especially absolute positioning.