Sure it is! It's all in the stylesheet.
The center part is controlled by
Code:
#mainWrapper {
background-color: #ffffff;
text-align: left;
width: 100%;
vertical-align: top;
}
These control parts of the side boxes
Code:
#navColumnOne {
background-color: #FFCC99;
}
#navColumnTwo {
background-color: #00BFBF;
}
Code:
.sideBoxContent {
background-color: #ffffff;
padding: 0.4em;
}
There are other settings you'll probably have to play with. I recommend getting Firefox and the web developers add-on which will allow you to play around with the stylesheet and see the effect immediately. When you're satisfied, you'll have to copy the changes, save them on your local computer and upload them to the site.