How to change timezone on ubuntu

One of my friend server must get reconfigure its clock each time, specially when the server get reboot after lamp problem.
Until he realized the timezone is different.
Here’s quick way to change it :

# dpkg-reconfigure tzdata

Current default timezone: ‘Asia/Jakarta’
Local time is now:      Sat Oct  3 13:02:53 WIT 2009.
Universal Time is now:  Sat Oct  3 06:02:53 UTC 2009.
Check

# date