Take a look at another site I run:
North American DotA Syndicate
I assume that's what you mean by the shadows on the sides (although a bit harder to see because of the dark striped background on the sides).
It's all about an image:
http://nadota.com/templates/ja_sanidineii_light/images/wrapper-bg.png
That background accounts for the light (almost white) background that the text is on, and also the shadows on the sides. It repeats vertically, but not horizontally (because it's already the width of the wrapper). So to achieve that, the wrapper div would have this background image, and no border (because the border is already in the image). This is why it's really nice to have some Photoshop experience when doing website development.