.comments-loading{display:block;}

<script>
        function isOnScreen(element){
            var curPos = $(element).offset();
            var curTop = curPos.top;
            var scrollTop = $(window).scrollTop();
            return (scrollTop < curTop);
        };
        $(function(){
            $(window).scroll(function() {
                if(isOnScreen('#comments')){
 $('.comments-loading').hide("slow",function(){
$('.comments-wrap').show(300);
});
                }
            })
        });
    </script>

<div id="comments">
<div class="comments-loading">
\img src="loading.gif" title="yorumlar yukleniyor" />
</div>
    <div class="comments-wrap">
        <div class="comment">1</div>
        <div class="comment">2</div>
        <div class="comment">3</div>
        <div class="comment">4</div>
        <div class="comment">5</div>
    </div>

yine kodda ufak tefek sorunlar cikabilir denemeden yaziyorum bu sekilde istedigin gibi olacak en basit hali ile