reviewing httpd access log

[J Moore <jaymo@cullmail.com>]

Reviewing my /var/www/logs/access_log file it seems there are a lot of 
"bogus" entries; i.e. people trying various hacks, looking for 
weaknesses, testing for win32, etc, etc.

Is there a good technique for automatically identifying these 
trouble-makers? I'd like to be able to build a "deny" table for pf to 
halt repeat offendors, but I can't afford the time to review the logs 
"manually".

Thanks,
Jay