Typically these "warnings" are the actual worm, which is waiting for you to do exactly that, send mail to everyone on your list, which it then copies and send off to its home site, and the spammers once again have a fresh list of people to harass. Thankfully its a hoax, but typically it is the actualy bug.
Wraith
Indeed. I wanted to pass it along in case it was real, but I also did not forward the actual email to anyone for exactly the reason you said. Normally I don't fall for those hoaxes, but today with a lot on my mind, my better judgement slipped momentarily.