Have you looked at your /etc/syslog.conf file? You may be logging more than you need. You can get by pretty well just logging like this:
There may be other entries in your /etc/syslog.conf, but this will get pretty much all you need. Also, if you have logging to /var/log/secure, or an security logging, I'd suggest leaving it alone. But if there is logging that is to echo directly to the console (i.e., mail.err console) you can probably comment it out so you won't get anything but *.crit (critical) messages echoed to the console screen.