At this time, there is no preferences application to set the timezone of your Openmoko device.
For now, either open the terminal application or log in to your Openmoko over the USB networking connection and change the timezone via commandline commands.
To change the timezone on your Freerunner you have to
opkg install tzdata
and then install one of these
tzdata-africa tzdata-americas tzdata-antarctica tzdata-arctic tzdata-asia tzdata-atlantic tzdata-australia tzdata-europe tzdata-misc tzdata-pacific tzdata-posix tzdata-right
after that, you should create a symlink named /etc/localtime which points to the appropriate file in /usr/share/zoneinfo. For example, if you're on the East Coast of the U.S., the following command will link the correct zoneinfo file to your /etc/localtime, giving you the correct time:
ln -sf /usr/share/zoneinfo/America/New_York /etc/localtime
for Germany for example it is TZ="Europe/Berlin" for France TZ="Europe/Paris" and so on
Alternatively, you can take the more invasive approach and change the TZ="UTC" in your /etc/profile to the timezone you want.
Once the timezone is set, restart of your x-server with
you should now have the right timezone.
In the future, expect the time zone to be set automatically by the telephone stack once connected to the network.
See also Date for setting the date and time.