Hi
I have just asked a question about a cron job for time syncing! I am running a script that does what you would like
#!/bin/bash
/etc/init.d/ntpd stop
wait ${!}
echo Syncing Time...
/usr/sbin/ntpdate 130.88.200.4
wait ${!}
/etc/init.d/ntpd start
wait ${!}
so if you put it in a folder in the /etc/cron.hourly folder, ours is called settime.sh, make it executable, and it should run every hour, syncing from an external time source. (in this case a manchester university NTP server)