Update: The patch for this security issue is now available from Microsoft @ http://www.microsoft.com/technet/security/bulletin/ms06-001.mspx. We suggest you immediately patch your system.
It's all over the net, and it's already infecting computer users worldwide exposing them to hackers. But, in case you have been caught napping it's the new "0-day Windows security flaw", which affects Windows XP, 2000 SP4, 2000 Server, Windows ME and even Windows 98, via e-mail or even simply by browsing Websites.
Though, there is no official patch yet from Microsoft but for the interim disable the Windows Picture and Fax viewer by clicking the Start menu, choose Run, then enter regsvr32 -u %windir%\system32\shimgvw.dll and click OK. Also ditch Microsoft Internet Explorer and get on to Firefox or Opera to browse Web sites.
Though the above is not going to completely defend your PC till Microsoft releases an official patch, it's the least you should do. We will keep you posted.