Graph template and data template for ntp stats. The required perl script is also included in the .tgz file.
Install ntp.pl into the scripts directory with proper permissions, and import the xml template. It may be necessary to adjust the path for ntpq in ntp.pl, if it differs from /usr/bin/ntpq on your machine.
Tested on Cacti versions 0.8.7g - 0.8.8b.
Depends on ntpq on machine running cacti.
11/11/2013: Edited included script to not perform DNS lookups, as this sometimes causes script timeouts and is unnecessary for graphing NTP data.