[Leprik]

<div id="top_link" class="top_link"><a href="#top">Подняться вверх</a></div>

/* set variables locally for increased performance */
	var scroll_timer;
	var displayed = false;
	var $top_link = $('#top_link');
	var $window = $(window);
	var top = $(document.body).children(0).position().top;
	/* react to scroll event on window */
	$window.scroll(function()
	{
		window.clearTimeout(scroll_timer);
		scroll_timer = window.setTimeout(function () { // use a timer for performance
			if($window.scrollTop() <= top) // hide if at the top of the page
			{
				displayed = false;
				$top_link.fadeOut(500);
			}
			else if(displayed == false) // show if scrolling down
			{
				displayed = true;
				$top_link.stop(true, true).fadeIn(500);
			}
		}, 100);
	});
	$top_link.find('a').click(function(e)
	{ 
		e.preventDefault();
		$(this).parent().fadeOut(500);
		$("html:not(:animated),body:not(:animated)").animate({ scrollTop : 0 }, 300);
	});