Your "site of the week" and "virus warning" each appear twice. Any reason for duplicating them?
As far as design, I'll give you credit for being one of the few who post their sites for review with a Doctype. Though, yes, the HTML isn't valid, it's a step in the right direction. Might I suggest a standard though. You have some tags in upper case, some in lower, some XHTML comliant (<br /> tags), and some not. Valid or not, it's best to pick some kind of standard and stick with it.