Ciao impostando il float left funziona eccoti il codice
<head>
<title>Esempio Div</title>
<style type="text/css">
body{
background:#FFF;
margin:0 auto;
padding:0;
width:1260px;
height:600px;
}
#header{
background-image:url(images/header.jpg);
background-repeat:no-repeat;
width:100%;
height:120px;
margin:0 auto;
}
#navigation{
background-color:#FFF;
width:100%;
height:430px;
margin:0 auto;
padding:0;
}
#testo_img{
background-image:url(images/testo-home-page.jpg);
background-repeat:no-repeat;
height:430px;
width:600px;
padding:0;
background-color:#000;
float:left;
}
#separatore{
width:25px;
height:300px;
padding:0;
margin:0 auto;
background-color:red;
float:left;
}
#menu{
width:20px;
list-style:none;
overflow:hidden;
width:100%;
float:left;
padding:1px;
margin:30px 0 0 0;
}
li{
display:inline;
} li.vocecorrente a{ /*caratteristiche della voce del menu selezionata*/
color:#FC0;
text-decoration: none;
}
a{
display:block;
float:left;
padding-rigth:90px;
height:25px;
margin-left:125px;
padding-left:65px;
font-family:Arial, Helvetica, sans-serif;
font-style:italic;
font-size:14px;
text-decoration:none;
color:#000;
line-height:25px;
} a:hover{
color:#FC0;
}
#footer{
margin:0 auto;
padding:0;
height:220px;
width:100%;
}
</style>
</head>
<body>
<div id="header">
<ul id="menu">
<li class="vocecorrente"><a href="home-page.html"><strong>Home</strong></a></li>
<li><a href="il-nostro-team.html"><strong>Il nostro Team</strong></a></li>
<li><a href="partners.html"><strong>Partners</strong></a></li>
<li><a href="#"><strong>Servizi</strong></a></li>
</ul></div>
<div id="navigation">
<div id="testo_img"></div>
<div id="separatore"><img src= "images/linea.jpg" width="17" height="300" /></div>
</div>
<div id="footer"></div>
</body>
</html>
