The infected person's Outlook Express has Yann's 
e-mail address in his/her address book.  With 
Klez, a spoofed e-mail is sent out with a random 
name chosen from the infected person's address 
book in the From field.

Basically, people just need to update their 
version of Outlook Express, or install a virus 
removal program.  There are even standalone free 
Klez removal utilities out there.

I get about 20 of these e-mails a day.  Fun fun, 
I tell ya.  Later.