sa-exim-stats generates spam/mail statistics from an sa-exim logfile. sa-exim is a patch for Exim which integrates SpamAssassin into Exim. The script's output includes: total spam messages, total clean messages, spam percentage, top n spam/clean/overal recipients. The script is designed so that it doesn't have to scan the entire logfile everytime it is run (status can be saved to a file or in a MySQL database). It can create and update a RRD database, and some basic PHP pages to display the graphs are included.
