There's a new e-mail virus going around according to a number of stories I've seen. Here's one account from All Headline News:
New Internet Virus Spreading Fast
The "Bagle" or "Beagle" worm arrives in an e-mail with the subject "hi" and the word "test" in the message body. If the accompanying attachment is executed, the worm is unleashed and tries to send itself to all e-mails listed in the user's address book.
As always, apply the latest patches, update your virus signatures, and encourage your friends and family to use caution when opening attachments in e-mail.
Here's a KB article that can help you secure a machine from theats like these. It might be a good idea to do this at home if you have kids or other family members who might not understand security: