From McAfee Threat Centre:
McAfee Labs has raised the Global Threat Condition to 'Critical'. Microsoft has released "Microsoft Security Advisory (979352) Vulnerability in Internet Explorer Could Allow Remote Code Execution". This vulnerability is actively being exploited in the wild. Exploit code for this vulnerability has been made public.
McAfee's George Kurtz is frequently blogging on this subject here.
Please be very vigilant during this time and ensure you keep your anti-virus software updated.
If you haven't already done so, I'd also recommend downloading McAfee SiteAdvisor which is free for home users.