desir,
Вариант...
<!DOCTYPE html>
<html>
<head>
<title></title>
<style type="text/css">
.header {
background: #c4dcf8 url(http://javascript.ru/forum/images/ca_serenity/misc/logo.gif) no-repeat right;
}
</style>
<script type="text/javascript">
var z = 0;
var stop = true;
function movesky() {
z++;
document.getElementById("header").style.backgroundPosition = z + "px 0px";
if (stop) {timerId = window.setTimeout(movesky,100); }
else stop = true
}
</script>
</head>
<body>
<div id="header" class="header">
<div id="headercontent">
<a id="buildings" onmouseover="movesky()" onmouseout="stop = false">главная</a>
<div id="tel">
<span>8 (495)</span> 000-00-00 <a href="#">контакты</a>
</div>
<div id="text">
<a href="#">» о компании</a>
</div>
</div><!-- #headercontent-->
</div><!-- #header-->
</body>
</html>