haber, checalo:
Código PHP:
<html>
<head>
<meta name="GENERATOR" content="Microsoft FrontPage 5.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>mmmmm....</title>
<title>Menu de navegacion desplegable</title>
<style type="text/css">
.tabla{background:#FF9900; color:black; font-weight:bold; font-family:verdana,arial; font-size:9; cursor:default;}
.sub{background:#FF9900; color:black; font-weight:bold; font-family:verdana,arial; font-size:9; cursor:default; visibility:hidden; position:relative; top:0; left:0;}
</style>
<script type="text/javascript">
//funcion que cambia el color de la celda
function cambiar(celda){
if(celda.style.background=="#FFCC00")
celda.style.background="#FFCC00" //color encima
else
celda.style.background="#FFCC00" //color inicial
}
//funcion que oculta/muestra el menu
function mostrar(menu){
if(document.all[menu].style.visibility=="visible")
document.all[menu].style.visibility="hidden"
else
document.all[menu].style.visibility="visible"
}
//funcion para posicionar
function posicionar(){
sm1.style.top=m1.style.top;
sm1.style.left=m1.style.left;
}
</script>
</head>
<body onLoad="posicionar()">
<div align="center">
<center>
<table border="1" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#C0C0C0" width="100%" id="AutoNumber1" height="100%">
<tr>
<td width="100%">
<div align="center">
<center>
<table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="700" id="AutoNumber2" height="500">
<tr>
<td width="200" valign="top" bgcolor="#CCCCCC">
<!-- Menu principal -->
<table class="tabla" border=1 bordercolor="black" cellpadding=3 cellspacing=0 align="center">
<tr>
<td onMouseOver="cambiar(this),mostrar('sm1')" onMouseOut="cambiar(this),mostrar('sm1')" id="m1">Enlace 1</td>
<td>Enlace 2</td>
<td>Enlace 3</td>
<td>Enlace 4</td>
</tr>
</table>
<!-- Primer submenu del menu desplegable -->
<div style="top:5;left:0;" onMouseOver="cambiar(this),mostrar('sm1')" onMouseOut="cambiar(this),mostrar('sm1')">
<table id="sm1" class="sub">
<tr><td>000000000000</td></tr>
<tr><td>111111111111</td></tr>
<tr><td>222222222222</td></tr>
<tr><td>333333333333</td></tr>
</table>
</div>
<br><br>
</td>
<td width="500" bgcolor="#E9E9E9"> </td>
</tr>
</table>
</center>
</div>
</td>
</tr>
</table>
</center>
</div>
</body>
</html>
espero y si te sirva.
Saludos !