Code
<div style="position:relative">
<a href="javascript://" style="position: fixed; bottom: 0px; right: 4px; display: block" id="toTop" onclick="$('body').scrollTo('0px',800, {axis:'y'})">
<img src="http://talk-forum.ucoz.ru/img/zp_scrolltop.png" border="0"/>
</a>
</div>