For next Tuesday, Microsoft announces to release 6 security bulletins. 3 of them deal with critical rated security vulnerabilities, which means that attackers can smuggle malware on the computer without (much) user interaction through the security holes.
The critical vulnerabilities are within the operating systems Windows 2000, Windows XP, Vista, Windows 7, Server 2003, Server 2008, also in Internet Explorer before version 8 (and also in IE8, there is another hole) and Microsoft Office XP and 2003. For the IE flaw there is exploit code already publicly available.
Windows users as well as administrators are well advised to prepare for December Black Tuesday and to roll out the Updates as soon as possible.