CSS Shadows all four sides of div

As Ventus said is not possible to use css shadows with ie (only ie9). But you can use shadowOn. It's a great jquery plugin and very easy in use. With it you will have cross browser compatibility.

CSS3pie is a tool that lets you use some css3 properties in IE.

What you're trying to do is fairly widespread css3 in newer browsers, and emulated really well (and easily) in IE with the .htc file you can download from there.

As for the markup, I see just 2 elements, with the top one floated right, for example. You'd have to play with z-index to hide excess shadows. In that site there's also a very similar effect, you should be able to adapt it for your needs.

Box Shadow works in all mordern [IE>8] browsers, This code uses no images and works in all browsers in IE versions below 9.

 box-shadow:2px 2px 10px 10px #C9C9C9;
 -webkit-box-shadow:2px 2px 10px 10px #C9C9C9;
 -moz-box-shadow:2px 2px 10px 10px #C9C9C9;

  /* For IE<9 */  
  filter:
  progid:DXImageTransform.Microsoft.Shadow(color=#C9C9C9,direction=0,strength=5),
  progid:DXImageTransform.Microsoft.Shadow(color=#C9C9C9,direction=45,strength=2),
  progid:DXImageTransform.Microsoft.Shadow(color=#C9C9C9,direction=90,strength=5),
  progid:DXImageTransform.Microsoft.Shadow(color=#C9C9C9,direction=135,strength=5),
  progid:DXImageTransform.Microsoft.Shadow(color=#C9C9C9,direction=180,strength=10),
  progid:DXImageTransform.Microsoft.Shadow(color=#C9C9C9,direction=225,strength=5),
  progid:DXImageTransform.Microsoft.Shadow(color=#C9C9C9,direction=270,strength=5),
  progid:DXImageTransform.Microsoft.Shadow(color=#C9C9C9,direction=315,strength=2);

Box shadow supported from IE 9 onwards.

This should work in all browsers:

    .allSidesShadow {
        box-shadow: 2px 2px 19px #aaa;
        -o-box-shadow: 2px 2px 19px #aaa;
        -webkit-box-shadow: 2px 2px 19px #aaa;
        -moz-box-shadow: 2px 2px 19px #aaa;

        /* For IE 5.5 - 7 */
        /* for IE4 - IE7 */
        filter:
            progid:DXImageTransform.Microsoft.Shadow(Strength=9, Direction=1, Color=#C4C4C4),
            progid:DXImageTransform.Microsoft.Shadow(Strength=9, Direction=90, Color=#C4C4C4),
            progid:DXImageTransform.Microsoft.Shadow(Strength=9, Direction=180, Color=#C4C4C4),
            progid:DXImageTransform.Microsoft.Shadow(Strength=9, Direction=270, Color=#C4C4C4);
        -ms-filter: "
            progid:DXImageTransform.Microsoft.Shadow(Strength=9, Direction=1, Color=#C4C4C4),
            progid:DXImageTransform.Microsoft.Shadow(Strength=9, Direction=90, Color=#C4C4C4),
            progid:DXImageTransform.Microsoft.Shadow(Strength=9, Direction=180, Color=#C4C4C4),
            progid:DXImageTransform.Microsoft.Shadow(Strength=9, Direction=270, Color=#C4C4C4)
        ";
    }