[tsigel]

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.js"></script>
<div class='one'>
  <div class='two' style='width: 200px; height: 100px; background-color: red'></div>
</div>

<button id='a'>Через find</button>
<button id='b'>$('.one .two')</button>

<script>
    $(function() {
        $('#a').click(function a() {
            $('.one').find('.two').css('background-color', 'green');
            return false;
        });

        $('#b').click(function() {
            $('.one .two').css('background-color', 'yellow');
            return false;
        });
    });
</script>