In the last 12h I've received a flurry of emails, sporting titles such as "Registration Confirmation", "You visit illegal websites" (from the FBI, nice ;-)), "Your IP was logged" (from the CIA, even nicer!), "Mail Delivery Failed", "Your Password", "hi, ive a new mail address", "Your password has been successfully updated" (from Mac.com), etc. They all include a ZIP file that itself contains a virus (infecting Windows).
It seems to be well spread and/or quite active, I've seen it on four addresses including a corporate one, and already received two reports from work, including the now traditional complaint that we're spamming people*.
Don't open attachements in unknown emails. And switch to Mac OS X or Linux if you can ;-).
(*) To circumvent anti-spam initiatives from ISPs, spammers now use spambots in the form of virus that infect Windows PCs (I've yet to see that on other OSes) and using those PCs to send spam through their own internet connection. They also crawl the user's disk drive to find email addresses and send spam to those, faking the "From:" address also from the harvested information. This explain why you can receive spam and viruses from companies or people you know, without them being involved in those activities (or even infected by those viruses). So, don't blame them too quickly.