Having correct time on a server is very important. For example, you cannot join a Windows PC to a Domain if the time differs more than a few minutes (Five minutes if I'm not mistaking).
To setup time zone and update time from internet on Ubuntu Server, do the following:
Check timezone
$ date Thu Mar 21 18:02:49 MST 2012
or check timezone file
$ more /etc/timezone Europe/Zagreb
Setup timezone
sudo dpkg-reconfigure tzdata
and follow the instructions
Also, be sure to restart cron as it will not be aware of the change otherwise
$ /etc/init.d/cron stop $ /etc/init.d/cron start
You can also update your time periodically by creating a daily crontab (crude but it works)
$ vim /etc/cron.daily/ntp
With the contents
#!/bin/sh ntpdate zg1.ntp.carnet.hr zg2.ntp.carnet.hr
and make sure to make it executable
$ chmod 755 /etc/cron.daily/ntp