I'd love to fix it, but I can't see it in any of my configurations (Linux/Windows, Opera/Firefox/Chrome/IE.)
I get the same extra box.
Using Safari 4.0.3 on Snow Leopard.
Hurk. Don't have a Mac. I'll see what I can do, though. I have an idea what's causing it.
I was able to reproduce with Chrome 3.0.195.27 on Windows; it's happening because Clicky Web Analytics has an image inside of a <p>, and you've styled p in footer to have a background image. I was able to get it to go away by removing the style, or by removing the p around the image in the footer.