fade in one at a time

HTML

<div id="one"></div>
    <div id="two"></div>
    <div id="three"></div>
    <div id="four"></div>

CSS

div { margin:3px; width:80px; display:none;
      height:80px; float:left; }
div#one { background:#f00; }
div#two { background:#0f0; }
div#three { background:#00f; }
div#four { background:#000; }

JavaScript

$("div").each(function(index) {
    $(this).delay(400*index).fadeIn(300);
});