CSS Image Drop Shadows is a Scripts software developed by Dynamic Drive. After our trial and test, the software is proved to be official, secure and free. Here is the official description for CSS Image Drop Shadows:

EditByMarydown: This examples shows how to add a drop shadow to any container element using CSS and the help of a large shadow image in the background. Virtually identical to the technique used to create a plain CSS shadow, the desired content is wrapped in a DIV with its background image set to an oversized shadow image. The content itself is relatively positioned and shifted slightly upwards and to the left to expose the shadow. A "master" DIV that surrounds the entire markup is also relatively positioned, but shifted to the right and downwards to return the entire markup to it's original position on the PaGE.

IE 6 has difficultly handling nested relatively positioned elements (YADA), so instead of letting IE6 ruin the fun for everyone else, we'll just use conditional HTML to hide the effect in that browser. IE7 is spared for finally learning proper CSS.