. . . it is a virus and a nasty one too. It can even appear to come from your own e-mail address -- mine did. Delete it immediately.
I think that the virus and spambot authors need to be dealt with the same way:
We unleash the hounds of hell
Chase them down whereever they live
Force them to their knees
Put a shotgun in their mouth like a big black cock of death and stroke the trigger.