CSS

.page_background {
     background-color: #FFFFFF;
     width: 924px;
     padding: 8px;
     margin-top: 0px;
     margin-right: auto;
     margin-left: auto;
     margin-bottom: 0px;
}
.page_background_shaddow_top {
     width: 950px;
     padding: 0px;
     margin-top: 10px;
     margin-right: auto;
     margin-bottom: 0px;
     margin-left: auto;
     background-image: url(images/background_drop_shaddow_top.gif);
     height: 5px;
}
.page_background_shaddow_middle {
     width: 950px;
     padding: 0px;
     background-image: url(images/background_drop_shaddow_sides.gif);
     background-repeat: repeat-y;
     margin-top: 0px;
     margin-right: auto;
     margin-bottom: 0px;
     margin-left: auto;
}
.page_background_shaddow_bottom {
     width: 950px;
     padding: 0px;
     background-image: url(images/background_drop_shaddow_bottom.gif);
     margin-top: 0px;
     margin-right: auto;
     margin-bottom: 10px;
     margin-left: auto;
     height: 5px;
}

HTML

<div class="page_background_shaddow_top">
</div>
<div class="page_background_shaddow_middle">
 <div class="page_background">


 </div>
</div>
<div class="page_background_shaddow_bottom">
</div>