Usa dei layer o meglio dei div dei quali cambi la visibilità con javascript.
Ecco un esempio creato al volo con Dreamweaver
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Untitled Document</title>
<script language="JavaScript" type="text/JavaScript">
<!--
function MM_reloadPage(init) { //reloads the window if Nav4 resized
if (init==true) with (navigator) {if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
function MM_findObj(n, d) { //v4.01
var p,i,x; if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
if(!x && d.getElementById) x=d.getElementById(n); return x;
}
function MM_changeProp(objName,x,theProp,theValue) { //v6.0
var obj = MM_findObj(objName);
if (obj && (theProp.indexOf("style.")==-1 || obj.style)){
if (theValue == true || theValue == false)
eval("obj."+theProp+"="+theValue);
else eval("obj."+theProp+"='"+theValue+"'");
}
}
//-->
</script>
</head>
<body>
<div id="Layer1" style=" background-color:#66FFFF; position:absolute; width:200px; height:115px; z-index:1; visibility: hidden; left: 318px; top: 142px;">
<div align="center">Esempio di prova creato da Claudioweb</div>
</div>
<span onMouseOver="MM_changeProp('Layer1','','style.visibility','visible','LAYER')" onMouseOut="MM_changeProp('Layer1','','style.visibility','hidden','LAYER')">Vieni qui col mouse</span>
</body>
</html>
Se cerchi su google trovi molti esempi simili.
Ciao
