Well, I'm half way home. Essentially, the code scrolls through a list. It works correctly for the "#last_button" but won't work for the "#first_button" and I'm not sure why. The only thing I can think of is that (".comment:last") is not returning the correct value. Thanks.

<script type="text/javascript">
$(document).ready(function(){

	$("#next_button").click(function(){
		var b = parseInt($(".comment:last").css("top"));
		if (b ==0) {
			$(".comment:last").css("top","0");
		} else {
			$(".comment").animate({top:"-=210px"},"fast");
		}
	});
	
    $("#last_button").click(function(){
		var a = parseInt($(".comment:first").css("top"));
		if (a ==0) {
			$(".comment:first").css("top","0");
		} else {
			$(".comment").animate({top:"+=210px"},"fast");
		}
		
	});
	
});

</script>