We checked this out on Snopes.com and it is a true virus -

It may come across your computer as a christmas greeting. New Facebook virus- Santa Claus isComing to Facebook to Infect Your Computer With Koobface [ALERT] Santa Claus is Coming to Facebook to Infect Your Computer WithKoobface [ALERT] The worm spreads as infected users post the greetings to the walls oftheir friends, who then in turn get infected when they check out thesupposed greeting. Here’s how Panda Security describes it:"Following the posting of malicious links on Facebook() users’ walls,the bait directs to a fake embedded video player that poses as aChristmas greeting. When users try to play the video or click on alink on the page, their computers download and install a variant ofthe well-known Koobface worm, Koobface.GK.After the virus is installed on a computer, a captcha is displayedthat threatens to reboot the computer within three minutes. Although nothing happens after three minutes, the computer is rendered useless.Every time a user enters the captcha text, Koobface.GK registers a newdomain where the infection files are hosted, facilitating the worm’scontinued distribution."Panda notes that holiday-themed malware has been a trend in recentyears, with malware distributors taking advantage of user’s propensityfor sending online greetings. Add social networking to the mix and youhave a medium where such scams can spread remarkably quickly.