как понимаю такое вот нужно:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" dir="ltr" lang="ru">
<head>
<style>
*, html{
margin: 0;
padding: 0;
}
#wrapper{
margin: 0 auto;
width: 990px;
background: #cecece;
}
#text_hidden{
display: none;
}
p{
line-height: 50px;
}
</style>
<script type="text/javascript">
function showHideText(e){
var e = e || window.event;
if (e.type == 'mouseover') document.getElementById('text_hidden').style.display = 'block';
else document.getElementById('text_hidden').style.display = 'none';
}
</script>
</head>
<body>
<div id="wrapper">
<div id="text">
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<div onmouseover="showHideText(event)" onmouseout="showHideText(event)">
наведи на меня
<div id="text_hidden">
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
<p>TEXT TEXT TEXT</p>
</div>
</div>
</div>
</div>
</body>
</html>