Timezones Help

Can anyone please help me get the following code to recognize the offset hours (i.e 3.5, -4.5)? It will only display the whole times the way it is but I need to get it to handle the offset times, too.

$timezones[-12] = "Eniwetok, Kwajalein";
$timezones[-11] = "Midway Islands, American Samoa, Gilbert Islands";
$timezones[-10] = "[Hawaii] Honolulu, Chatham Island, Papeete, Tahiti, Cook Islands";
$timezones[-9] = "[Alaska] Anchorage,Juneau";
$timezones[-8] = "[Pacific Time (US & Canada)] Los Angeles, Seattle, San Fransisco, Vancouver";
$timezones[-7] = "[Mountain Time (US & Canada)] Denver, Phoenix, Edmonton, Aklavik";
$timezones[-6] = "[Central Time (US & Canada)] Chicago, New Orleans, Houston, Winnipeg, St. Paul, Mexico City";
$timezones[-5] = "[Eastern Time (US & Canada)] New York, Miami, Boston, Atlanta, Montreal, Toronto, Lima, Bogota ";
$timezones[-4] = "[Atlantic Time (Canada)] Halifax, Caracas, La Paz, San Juan";
$timezones[-3.5] = "Newfoundland";
$timezones[-3] = "Brazil, Buenos Aires, Georgetown, Santiago, Asuncion, St. John's, Montevideo";
$timezones[-2] = "[Mid-Atlantic] Sao Paulo, Rio de Janeiro, Sandwich Islands";
$timezones[-1] = "Azores, Cape Verde Islands";
$timezones[0] = "[Western Europe Time] London, Lisbon, Dublin, Reykjavik, Casablanca";
$timezones[1] = "[CET(Central Europe Time)] Brussels, Rome, Paris, Amsterdam, Oslo, Z?rich, Madrid, Berlin";
$timezones[2] = "[EET(Eastern Europe Time)] Helsinki, Athens, Johannesburg, South Africa, Minsk, Cairo, Jerusalem";
$timezones[3] = "Moscow, St. Petersburg, Nairobi, Riyadh, Baghdad, Khartoum, Kuwait City, Addis Ababa";
$timezones[3.5] = "Tehran";
$timezones[4] = "Dubai, Abu Dhabi, Tbilisi, Muscat, Baku";
$timezones[4.5] = "Kabul";
$timezones[5] = "Ekaterinburg, Islamabad, Karachi, Tashkent";
$timezones[5.5] = "Bombay, Calcutta, Madras, New Delhi";
$timezones[6] = "Almaty, Dhaka, Colombo";
$timezones[7] = "Bangkok, Djakarta, Hanoi, Saigon, Phnom Penh, Christmas Island, Jakarta";
$timezones[8] = "Perth, Singapore, Beijing, Manila, Hong Kong, Taipei, Kuala Lumpur";
$timezones[9] = "Tokyo, Seoul, Osaka, Saporro, Yakutsk";
$timezones[9.5] = "Adelaide, Darwin";
$timezones[10] = "[EAST(East Australian Standard)] Brisbane, Guam, Vladivostok, Papua New Guinea";
$timezones[11] = "Sydney, Melbourne, Canberra, Magadan, Solomon Islands, New Caledonia";
$timezones[12] = "Auckland, Wellington, Fiji, Kamchatka";

$i=0;

while(list($timediff, $cities)=each($timezones)) {
	$i++;
	$servertime = $timeoffset - $timediff;
	$timestamp = mktime (date("H")-$servertime, date("i"), date("s"), date("m"), date("d"), date("Y"));
	$datetime = date($dateformat, $timestamp);
        $hourtime = date($hourformat, $timestamp);
        if ($timediff == $bbuserinfo[timezoneoffset]) {
		eval("\$localzone = \"".gettemplate('worldtimes_local')."\";");
	} else {
		eval("\$localzone = \"".gettemplate('worldtimes_notlocal')."\";");
	}
	eval("\$citycol .= \"".gettemplate('worldtimes_cols')."\";");
	if($i % $perrow == 0) {
		eval("\$cityzones .= \"".gettemplate('worldtimes_rows')."\";");
		unset($citycol);
        }

}

eval("dooutput(\"".gettemplate('worldtimes')."\");");