Как вариант...
<!DOCTYPE html>
<html>
<head>
<script src='http://code.jquery.com/jquery-latest.js'></script>
<!--
<link rel='stylesheet type=text/css href=tmp.css' />
-->
<style type='text/css'>
</style>
<script type='text/javascript'>
$(function (){
$('#search').keyup(function (){
var val=this.value;
$('#cars .brand:contains("'+val+'")').parents('li').show();
$('#cars .brand:not(:contains("'+val+'"))').parents('li').hide();
});
});
</script>
</head>
<body>
<input type="text" maxlength="30" placeholder="Поиск..." id="search" />
<ul id="cars">
<li><a href="#"><span class="brand">Alfa Romeo</span></a></li>
<li><a href="#"><span class="brand">AC</span></a></li>
<li><a href="#"><span class="brand">Alpina</span></a></li>
<li><a href="#"><span class="brand">Bertone</span></a></li>
<li><a href="#"><span class="brand">Briliance</span></a></li>
<li><a href="#"><span class="brand">Baltijas Dzips</span></a></li>
<li><a href="#"><span class="brand">Cadillac</span></a></li>
</ul>
</body>
</html>