Ok, I am dumb! It is located in /var/log/mail.log
I guess I didn't notice the "smtpd" line previously so I assumed there was a different file for this. Thanks anyway.
Ok, next question. Does anyone know of a better application for viewing/searching log files other than the built-in Console. I guess what I am looking for in a Console like program is the ability to show the line number, like in "vi". Also, does "vi" give you the ability to read ".gz" files, then I could do all this in "vi".