This is the klez virus. It harvests email addresses from messages and addressbooks and sends email to random addresses as that email address. It is seldom (or never) the address that it says that is infected and has sent that mail.

As I work on the Help Desk at a University I encounter it almost daily in the form of returned emails that were never sent by the people they purport to have been sent by.

snippet of text taken from symantec http://securityresponse.symantec.com/avcenter/venc/data/w32.klez.h@mm.html
:

Email:
This worm searches the Windows address book, the ICQ database, and local files for email addresses. The worm sends an email message to these addresses with itself as an attachment. The worm contains its own SMTP engine and attempts to guess at available SMTP servers. For example, if the worm encounters the address user@abc123.com it will attempt to send email via the server smtp.abc123.com.

The subject line, message bodies, and attachment file names are random. The From address is randomly-chosen from email addresses that the worm finds on the infected computer.

hah. lucky that The Bat! is invulnerable to Klez

I get one of those every other day or so....

Crae...I've still got some Sircam32 you can have....I'll sell it to you cheap....