ciao...e' questo quelllo che vuoi ?
codice:
<!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" xml:lang="it" lang="it" dir="ltr"> 
<head> 
 
<title>Centrare verticalmente un oggetto in un contenitore</title> 
 
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> 
<style type="text/css" media="screen"> 

html, body{ 
margin:0; 
padding:0; 
font-family: "Trebuchet MS", Georgia, Verdana, sans-serif; 
text-align:center; 
} 

#main { 
	position:absolute; 
	margin-top:15px;
	left:130px;
	width:750px; 
	height:750px; 
	background:#FFFFFF; 
	text-align:left;
	letter-spacing: normal; 
	word-spacing: normal; 
	border:2px solid red; 
} 

#banner{ 
	position:relative; 
	margin-top:0;
	margin-left:0;
	background:#666666; 
	width:100%; 
	height:99px; 
} 
#container{
	position:absolute;
	border:1px solid blue;
	width:300px;
	height:400px;
	margin-top:100px;
	margin-left:30px;
	padding:2px;
	font-family:Arial, Helvetica, Time New Roman;
	font-size:10pt;	
}

#container2{
	position:absolute;
	border:1px solid blue;
	width:300px;
	height:400px;
	margin-top:100px;
	margin-left:410px;
	padding:2px;
	font-family:Arial, Helvetica, Time New Roman;
	font-size:10pt;	
}

</style> 
 
</head> 


<body> 
<div id="main"> 
<div id="banner">[img]../Hintergrund/HEADER.jpg[/img]</div> 
<div id="container">Questo e' i ltesto del contenitore uno</div>
<div id="container2">Questo invece lo e' del contenitore 2</div>
</div> 


</body> 
</html>
Se si, io ti consiglierei di inserire il codice dei css su un file a parte chiamato style.css ed importarlo nel documento con la sintassi
codice:
<style>\n";
  @import url(style.css);
</style>\
ciao a presto.