Shadow borders in CSS

I want to be able to create the shadow borders that you find on CSS built sites such as site example . i;ve tried a tutorial that I [URL=http://old.thoughtanomalies.com/archives/2004/06/20/fluid_shadows/]found here but I couldn’t get it to work. The page laid out but the shadows didnt appear as I tried to make my own gif shadows.

Can anyone help me with this tutorial, point me in the dirrection of another one or tell me what I need to know.

Thanks