I have been getting a spam coming through my messaging service (like
it was sent using net send).  I have been unable to find out who is
sending this message.  Is there a way to track the IP of messages like
this, or preferably stop the messages coming from certain IPs (without
turning of the messaging service)?

Dear mmoosman:

Thank you for your question. 

The IP address or username of the user who is sending you the message
should be visible in the message window of net send. If it is not
showing up, then you can use this Bopup Observer, a shareware product
to view advanced details, log, and even block IP addresses of Net Send
and Winpopup messages.

The homepage of the product is here:
http://www.bopup.msk.ru/products/observer/

Overview

Bopup Observer is an instant messenger, which allows you only to
receive messages. It is completely compatible with standard programs
and catches messages from WinPopup, Net Send and Bopup Messenger.
Bopup Observer features include

    * Full compatibility with standard utilities
    * URL's, Internet and Network addresses support
    * View advanced details about received message
    * Ignore List
    * Network Groups
    * Message History
    * Receiving files
    * Terminal Server support
    * Bopup Group Server support

Google Search Strategy:

"net send"
"net send" ip address
ip address blocking "net send"

I hope this was the information you were looking for! If you need any
clarifications, please don't hesitate to ask. I would be more than
happy to assist you further.

Best Regards,
blader-ga

Looks like exactly what I was looking for.  I also noted the
information from moot thanks.

Thanks for the, very, quick response.

you are gettin hit with a new spam tool, see
http://www.wired.com/news/technology/0,1282,55795,00.html

Did you happen to receive advertisements for a university diploma?

Yes, I am getting ads about a university diploma?  I have also got a
few telling me to complain to Microsoft.  Both are obvious scams.

You may also want to check out: 
http://www.visualware.com/emailtrackerpro/index.html

Babs.

In my opinion the best way to do this would be to go to this website
and lookup the IP address.  Any IP address owned by a recognized
company should be listed here.

http://www.arin.net/index.html