Im trying to make this menu abit more accessible by using css - but failing!

can anyone help me further, so far ive got

HTML Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<style>

body {
	font-family: arial, helvetica, serif;
}

ul { /* all lists */
	padding: 0;
	margin: 0;
	list-style: none;
}

li { /* all list items */
	float: left;
	position: relative;
	width: 120px;
	border: 1px solid #FFFFFF;
	background-color: #ffd100;
	font-family: Arial, Helvetica, sans-serif;
	font-size: 12px;
	color: #FFFFFF;
	font-weight: bold;
	height: 25px;
	padding-top: 10px;
	padding-left: 5px;
	padding-right: 0px;
	padding-bottom: 0px;
}

li ul { /* second-level lists */
	display: none;
	position: absolute;
	top: 1em;
	left: 0;
	font-family: Arial, Helvetica, sans-serif;
	font-size: 12px;
	color: #FFFFFF;
	padding-top: 23px;
	padding-right: 0px;
	padding-bottom: 0px;
	padding-left: 0px;
}

li>ul { /* to override top and left in browsers other than IE, which will position to the top right of the containing li, rather than bottom left */
	top: auto;
	left: auto;
}

li:hover ul, li.over ul { /* lists nested under hovered list items */
	display: block;
}

#content {
	clear: left;
}
a.white:link {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 12px;
	color: #FFFFFF;
	text-decoration:none;
}
a.white:visited {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 12px;
	color: #FFFFFF;
	text-decoration:none;
}
a.white:active {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 12px;
	color: #FFFFFF;
	text-decoration:none;
}
a.white:hover {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 12px;
	color: #FFFFFF;
	text-decoration:none;
}
</style>

<head>
<title></title>
<script type="text/javascript"><!--//--><![CDATA[//><!--
startList = function() {
	if (document.all&&document.getElementById) {
		navRoot = document.getElementById("nav");
		for (i=0; i<navRoot.childNodes.length; i++) {
			node = navRoot.childNodes[i];
			if (node.nodeName=="LI") {
				node.onmouseover=function() {
					this.className+=" over";
				}
				node.onmouseout=function() {
					this.className=this.className.replace(" over", "");
				}
			}
		}
	}
}
window.onload=startList;

//--><!]]></script>

</head>

<body>

<ul id="nav">

	<li>Home
		<ul>
			<li><a href="about.html" class="white">About Us</a></li>
		</ul>
	</li>

	<li>Properties to Rent
		<ul>
			<li><a href="search.html" class="white">Property Search </a></li>
			<li><a href="register.html" class="white">Register / Login</a></li>
		</ul>
	</li>

	<li>Tenants
		<ul>
			<li><a href="tenantguide.html" class="white">Tenant Guide</a></li>
	
		</ul>
	</li>
	<li><a href="landlords.html" class="white">Landlords</a>
		<ul>
			<li><a href="landlords.html#levelofservice" class="white">Level or Service</a></li>
			<li><a href="landlords.html#choosinganagent" class="white">Choosing an Agent</a></li>
			<li><a href="landlords.html#saftyinformation" class="white">Saftey Information</a></li>
			<li><a href="landlords.html#furniture" class="white">Furniture &amp; Furnishings</a></li>
			<li><a href="landlords.html#financialobligations" class="white">Financial Obligations</a></li>
			<li><a href="landlords.html#counciltax" class="white">Council Tax</a></li>
			<li><a href="landlords.html#utilities" class="white">Utilities &amp; Service Providers</a></li>
			<li><a href="landlords.html#inventories" class="white">Inventories</a></li>
			<li><a href="landlords.html#inlandrevenue" class="white">Inland Revenuex</a></li>
			<li><a href="landlords.html#insurance" class="white">Insurance</a></li>
			<li><a href="landlords.html#keys" class="white">Keys</a></li>
			<li><a href="landlords.html#legalaspects" class="white">Legal Aspects</a></li>
		</ul>
	</li>
	<li><a href="cityliving.html" class="white">City Life</a>
		<ul>
			<li><a href="cityliving.html#living" class="white">Living in Newcastle</a></li>
			<li><a href="cityliving.html#eating" class="white">Eating &amp; Drinking</a></li>
			<li><a href="cityliving.html#transport" class="white">Local Transport</a></li>

		</ul>
	</li>
	<li><a href="contactus.html" class="white">Contact Us</a>

	</li>

</ul>

</body>

</html>
Thanks in advance