This is a simple tutorial on how to install and configure the NTP service to make sure your clock is accurate and synched on your system.
$ yum install ntp
Once that's done turn on the NTP service so that it automatically starts on boot.
$ chkconfig --level 2345 ntpd on
Here we are just setting the service the NTP server will use to synchronize the clock with, in this case we are using the 0.pool.ntp.org
server
$ ntpdate pool.ntp.org
$ /etc/init.d/ntpd start