Appolo,

One can spoof email addresses, if he knows the mail server of the domain, and has and idea as to how it is configured.
There are methods of telneting and sending spoofed emails...

I think, in spoofed emails one cannot specify the "From : " NAME.
So if the incoming message contains "From : " and "only the email address",but no name, then there are chances that it is a spoofed email.

Hope that helps.
Cheers.