The Valentine's Day Storm Worm virus is out there. The Storm Worm virus has used other holidays, especially those associated with greeting cards.
The virus is delivered in a bogus email that directs users to click on a link in order to receive an electronic greeting card. What really happens is some really nasty software (a.k.a. malware) is installed on the user's computer, making it part of what is called a "botnet"--a network of computers that have been taken over by malware for illegal purposes.
The F.B.I. issued a press release about it.
And here is a good Snopes.com entry on the virus that provides a list of subject messages to be on the look out for.
When in doubt, delete a suspicious email. And, keep your anti-virus software up-to-date, not only to protect your system, but also to facilitate cleaning it out if it gets infected.
The go-to site for all things related to computer viruses and Internet crime: ic3.gov.