box-shadow for Opera, Gecko, Webkit and IE8.

box-shadow.css

.box-shadow {
	-webkit-box-shadow: 0 1px 3px #aaa; /* Webkit */
	   -moz-box-shadow: 0 1px 3px  #aaa; /* Gecko */
	        box-shadow: 0 1px 3px #aaa; /* CSS3 default, should be after vendor-specific properties */
	-ms-filter: "progid:DXImageTransform.Microsoft.Shadow(color='#aaaaaa', Direction=0, Strength=2)
		progid:DXImageTransform.Microsoft.Shadow(color='#aaaaaa', Direction=45, Strength=1)
		progid:DXImageTransform.Microsoft.Shadow(color='#aaaaaa', Direction=90, Strength=2)
		progid:DXImageTransform.Microsoft.Shadow(color='#aaaaaa', Direction=135, Strength=1)
		progid:DXImageTransform.Microsoft.Shadow(color='#aaaaaa', Direction=180, Strength=2)
		progid:DXImageTransform.Microsoft.Shadow(color='#aaaaaa', Direction=225, Strength=1)
		progid:DXImageTransform.Microsoft.Shadow(color='#aaaaaa', Direction=260, Strength=2)
		progid:DXImageTransform.Microsoft.Shadow(color='#aaaaaa', Direction=305, Strength=1)";  /* IE8 */
}