I came across a very useful little set of perl scripts
packaged together as Logwatch (http://www2.logwatch.org:81/index.html).
This wonderful set of tool will parse
your logs and then email a daily report with all of the important statistics
and data in one place. The package is
easily configured and can be used to parse archive logs too; meaning even high
throughput systems (e.g. email) can be monitored and reported on. I found this while snooping around for an
application or script to extract useful information and statistics from our
postfix logs, due to some stability issues we have been experiencing.
There are loads of similar log analysing programs out there;