The tenth variant of the virus Bagle has now been released. This one is a bit smarter than the others in three ways. It lists it's sender address as your domain, so for Techspot I for example got an e-mail from email@example.com (which is a nonexistant address btw)
The content of the e-mail is changed to reflect this, so it reads as it comes from the Techspot division bla bla....
The smartest thing is that in the e-mail the password is given for the attached compressed encrypted file, what this means is that any e-mail gateways will fail to find the virus since it is encrypted, thus bypassing any security measures and allowing the virus to end up at the local workstations inside your networks. Take big note of this admins!
Here is a page on F-Secure with further details on the virus.