A ver si te sirve esta solución:
Cita: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>2 Columns</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style type="text/css">
* {
padding: 0;
margin: 0;
}
html, body {
height: 100%;
}
html, body {
behavior: url(resources/htc/hover.htc);
background-color:#FFFFFF;
}
#wrap {
margin:0 auto;
width:100%;
height: 100%;
}
#header {
height:66px;
background-color:#999999;
width:100%;
position: absolute;
top 0px; left: 0px;
}
#main {
background:#9c9;
float:left;
width:185px;
height:100%;
}
#sidebar {
background:#99c;
width:100%;
height:100%;
}
.relleno {height: 70px;}
</style>
</head>
<body>
<div id="wrap">
<div id="header">header</div>
<div id="main"><div class="relleno"></div>menu</div>
<div id="sidebar"><div class="relleno"></div>content</div>
</div>
</body>
</html>
Mikel.