Here's some general guidance that we're pushing in the wake of the Bagle virus:

Bagle Virus Notice: What to Do
Treat all e-mail attachments with caution, even if they appear to be from a trusted source. Learn what to do about virus infections.
http://www.microsoft.com/security/articles/remedies_viruses.asp

This is mostly for consumers, so you can send that link to friends and family who might be having trouble or who are asking questions about viruses.