We've had a few Netsky's come in, no biggie though. It didn't actually come through the corperate e-mail system (before the mail even hits the main SMTP Server, it's scanned by 2 different MIME scanner), but stupid 3rd party web-mails (which we've BANNED by policy, but users keep using them).
Fortunately, there is no real damage in the payload, thank god. And it's an easy clean-up.
Z