Some quick notes.
# Remove old syslog-ng package
pkg_info | grep syslog-ng
pkg_delete syslog-ng-1.6.12_1
# Installing new version
setenv PACKAGESITE
http://files.pfsense.org/packages/amd64/8/All/
ftp://ftp4.freebsd.org/pub/FreeBSD/ports/i386/packages-stable/Latest/
pkg_add -r syslog-ng
# Make sure there is a /usr/local/etc/syslog-ng.conf
# Autostart syslog-ng, edit /etc/rc.conf.local
syslog_ng_enable=“YES“
# Disable default syslog, /etc/rc.conf.local
syslogd_enable=“NO“
# Kill syslogd, start syslog-ng
kill `cat /var/run/syslog.pid`
/usr/local/etc/rc.d/syslog-ng start
Sources:
http://forum.pfsense.org/index.php?topic=3976.0
http://forum.pfsense.org/index.php/topic,7793.0.html
http://www.mail-archive.com/discussion@pfsense.com/msg02764.html
FreeBSD based version info: http://doc.pfsense.org/index.php/PfSense_and_FreeBSD_Versions