I just got a popup security alert from my Avast anti-virus program. It is telling me of a new hacking threat called "iframe", which apparently is a malicious script called "HTML:Iframe-inf". Anyway, the crazy thing about this, is that your PC can get infected just by visiting trusted, legitimate commercial sites.
Here's the official Avast report detailing on exactly how this malware operates: http://www.avast.com/eng/avast-and-forum-users-combine-to-defeat-website-hackers.html