Configure time zone(HELP)

Hi there,

I am having some minor difficulties on configuring the time zone.

Here is the line:

$thedate=date("U"); //get unix timestamp
$displaytime=date("F j, Y, g:i a");

The line above not displaying the correct time zone where I currently in. I want to set the time zone to UTC+8.00.

How to set it? Please advise.