I have been getting reports of various ZIP files with EXE content getting through people Symantec Mail Security and McAfee scanners. This is with the definitions dated the 24th September 2006.
In GFI Mailsecurity, the attachment is detected as "Generic.Stration.74C486D4"
Our own server, which rarely gets hit with viruses has reported over 100 blocked mails (GFI Mailsecurity) in the last two hours! Tell your users to be careful opening attachments!