allora,
se lo fai con i div il codice è il seguente

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Documento senza titolo</title>
<style type="text/css">
<!--
.divheader {
font-family: Arial, Helvetica, sans-serif;
font-size: 16px;
font-style: normal;
text-transform: capitalize;
color: #FFFFFF;
text-decoration: none;
background-color: #999999;
text-align: right;
padding: 5px;
height: 150px;
width: 100%;
border-bottom-width: 1px;
border-bottom-style: solid;
border-bottom-color: #000000;
}
body {
background-color: #999999;
margin: 0px;
}
.divbody {
background-color: #333333;
margin: 0px;
height: 300px;
width: 100%;
overflow: auto;
}
-->
</style>
</head>

<body>
<div class="divheader">Inserire qui il contenuto per class "divheader"</div>

<div class="divbody">Inserire qui il contenuto per class "divbody"</div>
</body>
</html>