Mailreport is a powerfull tool to analyse mail log file, all explicit pattern
are saved in a MYSQL database.
You can automate this process with the crontab.
HTML report are created in real time, based on a perl script (you need mod_perl
with your apache server).
It support international languages (English, and French now).
You can enable support for a particular domain and disable stored of the amavis log.
Screenshots are available here1 and here2.
Current version is 0.95, it can be download here.