Connect to your Virtual Server via Telnet or SSH and follow the directions below.

USA Time Zones
To change the time zone on your Virtual Server to the USA Pacific Standard Time zone (for example), issue the following commands according to your Virtual Server O/S:

FreeBSD
% chmod 600 ~/etc/localtime
% cp /usr/share/zoneinfo/America/Los_Angeles ~/etc/localtime

BSD/OS
% chmod 600 ~/etc/localtime
% cp /usr/share/zoneinfo/posix/US/Pacific ~/etc/localtime

Here is a list of available USA time zones 
(substitute one of these for America/Los_Angeles or Pacific above):

FreeBSD
America/New_York        Eastern Time
America/Detroit         Eastern Time - Michigan - most locations
America/Louisville      Eastern Time - Louisville, Kentucky
America/Indianapolis    Eastern Standard Time - Indiana - most locations
America/Indiana/Marengo Eastern Standard Time - Indiana - Crawford County
America/Indiana/Knox    Eastern Standard Time - Indiana - Starke County
America/Indiana/Vevay   Eastern Standard Time - Indiana - Switzerland County
America/Chicago         Central Time
America/Menominee       Central Time - Michigan - Wisconsin border
America/Denver          Mountain Time
America/Boise           Mountain Time - south Idaho & east Oregon
America/Shiprock        Mountain Time - Navajo
America/Phoenix         Mountain Standard Time - Arizona
America/Los_Angeles     Pacific Time
America/Anchorage       Alaska Time
America/Juneau          Alaska Time - Alaska panhandle
America/Yakutat         Alaska Time - Alaska panhandle neck
America/Nome            Alaska Time - west Alaska
America/Adak            Aleutian Islands
Pacific/Honolulu        Hawaii

BSD/OS
Alaska, Central, Hawaii, Mountain, Aleutian, East-Indiana, Indiana-Starke,
Pacific, Arizona, Eastern, Michigan, Samoa

European Time Zones
To change the time zone on your Virtual Server to the Greenwich Mean
Time zone (for example), issue the following commands according to your Virtual Server O/S:

FreeBSD
% chmod 600 ~/etc/localtime
% cp /usr/share/zoneinfo/Europe/London ~/etc/localtime

BSD/OS
% chmod 600 ~/etc/localtime
% cp /usr/share/zoneinfo/posix/Europe/London ~/etc/localtime

Here is a list of possible European time zones (substitute one of these for London above):

FreeBSD
Amsterdam, Andorra, Athens, Belfast, Belgrade, Berlin, Bratislava,
Brussels, Bucharest, Budapest, Chisinau, Copenhagen, Dublin, Gibraltar,
Helsinki, Istanbul, Kaliningrad, Kiev, Lisbon, Ljubljana, London,
Luxembourg, Madrid, Malta, Minsk, Monaco, Moscow, Oslo, Paris, Prague,
Riga, Rome, Samara, San_Marino, Sarajevo, Simferopol, Skopje, Sofia,
Stockholm, Tallinn, Tirane, Vaduz, Vatican, Vienna, Vilnius, Warsaw,
Zagreb, Zurich

BSD/OS
Amsterdam, Andorra, Athens, Belfast, Belgrade, Berlin, Bratislava,
Brussels, Bucharest, Budapest, Chisinau, Copenhagen, Dublin, Gibraltar,
Helsinki, Istanbul, Kiev, Kuybyshev, Lisbon, Ljubljana, London,
Luxembourg, Madrid, Malta, Minsk, Monaco, Moscow, Oslo, Paris, Prague,
Riga, Rome, Sarajevo, Simferopol, Skopje, Sofia, Stockholm, Tallinn,
Tirane, Vaduz, Vienna, Vilnius, Warsaw, Zagreb, Zurich

Other Time Zones
There are many more time zones in these directories:

FreeBSD
/usr/share/zoneinfo

BSD/OS
/usr/share/zoneinfo/posix

Did It Work?
To make sure you set the time zone correctly on your Virtual Server do the following:

% virtual date

Now, restart your Virtual Server Apache Web Server 
so that it will use the new time zone you have set:

% restart_apache