A secure democratic Net is a fundamental right

http://www.theregister.co.uk/2008/12/04/zip_malware_attac...

So if you receive a mail - that you didn't aks for - promising free airline tickets, a freelance job, a change of user contract or another famous brand, you better watch out.

If there is a zipfile included, it doesn't seem intelligent to open (or to send as a firm zipfiles as attachments) 

And if in reality it is not send by the domainname of the firm, it is definitively spam.

The best way is to treat that kind of garbage mail first on your webmail (hotmail, gmail, yahoo, whatever) and only download every so many weeks some older mails that have been checked and rechecked and survived the virus scans. 

If you take your mail in yourself you should be sure that your antivirus is up to date and is a good one because otherwise you will get infected