Hi jdurkot,
They are probably fake messages. Now it's common, unfortunately... some spammers are sending fake messages to force the recipient to open them and than verifying that e-mail address is valid, or to install a malware or spyware or even a virus.
If a virus on your system had sent itself to your contact list, you'll surely receive some warning from some of your friends or contacts.
It's recommended to not open it (I let the view pane of my Outlook express deactivated, so I can delete them without viewing. when I am in doubt, i take a look on them by right-clicking and opening message source on properties tag).
By the way, Spybot S&D is a good program, but it's not sufficient. I recommend you to download and run AdAware SE and SpywareBlaster (after update them).
It's also wise to check for viruses on some housecall online.
Chris
Hi Steve... I was answering at the same moment. I's a possibility, but I have received a lot of fake message with headers like that, most of them containing some counter, or script to trace opening