It is actually possible to achieve this effect using CSS3 in newer browsers and filters in IE. I came across a truly informative article that explained how it can be done. By simply adding the following CSS code to a div, you can create a shadow effect that works seamlessly on FF, Safari, Chrome, Opera, as well as IE versions 5.5 and above.
.module {
/* offset left, top, thickness, color with alpha */
-webkit-box-shadow: 5px 5px 5px rgba(0, 0, 0, 0.5);
-moz-box-shadow: 5px 5px 5px rgba(0, 0, 0, 0.5);
box-shadow: 5px 5px 5px rgba(0, 0, 0, 0.5);
/* IE */
filter:progid:DXImageTransform.Microsoft.dropshadow(OffX=5, OffY=5, Color='gray');
/* slightly different syntax for IE8 */
-ms-filter:"progid:DXImageTransform.Microsoft.dropshadow(OffX=5, OffY=5, Color='gray')";
}