As system admin for the company that employs me, I do have quite some experience with computer security issues. Larry is correct in that it is definitely the Fizzer worm. I personally have not received it but ladylightkeeper forwarded me hers and I analyzed it. It looks to me like the email headers have definitely been forged to look like Saint John sent it when in fact he really did not. This is quite a common ploy among these scumbags. It happens to me pretty regularly.

I too will emphasize the importance of running a reputable virus scanner on your PC and keeping it updated regularly.