This forum is for OneCare antivirus questions/issues so this is a bit off-topic.
The message you pasted is a well-known hoax, as noted in the Snopes article. There is not a new, urgrent threat spreading that antivirus vendors are "gearing up for" and that was recently reported by CNN and/or Microsoft as the "most destructive virus ever" and that destroys your hard disk and so forth. The hoax assumes that you'll glance at the Snopes article and see that it is "confirmed" and forward the message on without reading the article, annoying your family and friends.
However, there are indeed plenty of malware threats that pretend to be electronic greeting cards in order to trick users into running a malicious program or visiting a malicious Web site (also as noted in the Snopes article).
As always, run a well-respected antimalware program and keep it up-to-date. Use caution when opening unexpected attachments, even if they're from people you know (a best practice is to contact the sender and get confirmation that they meant to send you the attachment before opening it).
Randy