You are in a business trip to Singapore, but your iPhone 3G prefers to be in a different time zone. Reportedly, some units have shown a special urge to go back to the Cupertino time zone. Some other units would rather prefer to display U.S., Pacific Coast time or GMT.

That’s annoying. But luckily there is a way to fix that. Update the iPhone OS to 2.0.2.
If the problem persists, try switching off the iPhone. Then take out and replace the SIM. Restart the iPhone and “Reset All Settings”. Setting the right time zone after this should give you the time you want.