on shell, my server time is (simple date in bash):
Sun Aug 29 10:37:12 EDT 2010
when I run the code php -r \"echo date(\'Y-m-d H:i:s\');\"
According to the php.ini directives manual page, the timezone isn't set by default if you're using a version prior to 5.3. Then if you take a look at the page for date_default_timezone_get, it uses the following order for getting the timezone:
* Reading the timezone set using the date_default_timezone_set() function (if any)
* Reading the TZ environment variable (if non empty) (Prior to PHP 5.3.0)
* Reading the value of the date.timezone ini option (if set)
* Querying the host operating system (if supported and allowed by the OS)
UTC is the default if all of those fail, so that's probably a good starting point.