Apparently, WordPress is vulnerable to some script injection bugs, and this site was hit by them. And Google tagged the site as "spreading malware", so the site shows up with a warning in Google search results and FF3 users can't get to it at all. I've upgraded Wordpress, scoured the DB for injected scripts, and am in the process of begging google to let me off the blacklist.
What a pain in the butt. People suck.