***********************************
         * !!!!!!!!!!! WARNING !!!!!!!!!!! *
         ***********************************

A startup script, named sancp.sh-sample was installed in
%%PREFIX%%/etc/rc.d/.  Create a copy named sancp.sh in the
same directory and enable the script in /etc/rc.conf using 
the usual rc.subr syntax.  See rc.conf(5) or go to
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/configtuning-rcng.html

Configuration files named sancp.conf-sample and sancp.conf
were installed in %%PREFIX%%/etc.  See the INSTALL doc, located in
%%PREFIX%%/share/doc/sancp/ for details on configuration 
options or type "sancp -h" on the commandline.

Note that if you are installing sancp for use with sguil, the 
sancp.conf file will not be altered unless it is identical to
the sancp.conf-sample file.  In that case, during the 
sguil-sensor install, the sancp.conf file will be overwritten with
the one that comes with squil.  That file needs no editing.  If the
sancp.conf has been altered (you used sancp for something else) a 
new conf file, named sguil-sancp.conf-sample will be installed in the 
%%PREFIX%%/etc/rc.d/directory.  You should use that one for sguil.

Some of the configuration options for sancp are:

-? or -h  this help screen
-c <filename>  specify the configuration/rules filename
-d <directory>  specify the directory for output files
-i <device>  set the network device to listen on (default: 'any')
-g <gid>   set a group identity
-u <uid>   set a user identity
-D (daemon) forks, prints msgs to syslog only and overrides -C option
-F <bpf filename>  file containing a bpf filter expression, overrides (alternative to -B)
-V  display version

If you're running sguil, you probably want to use the following flags:
sancp_flags="-D -P -R -u sancp -g sancp -d /var/log/sancp"
(don't forget to specify the conf file and interface as well)