How can I find country name -> GMT date/time to that I can do like following:
Example:
$datetime = new GMT_search(\'America\'); //output: 2010-01-01
Not sure if this is what you are looking for but PEAR has a "Date" package available that has a nice example that seems to do what you are asking for.
http://pear.php.net/manual/en/package.datetime.date.examples.php (scroll down to "Converting timezones")