If the server is not using PHPSuexec, then your scripts are probably running as nobody. If it is using PHPSuexec, then they'll be running as your hosting account username.
create a phpinfo page on your site somewhere to check: http://www.zend.com/manual/function.phpinfo.php
create a phpinfo page on your site somewhere to check: http://www.zend.com/manual/function.phpinfo.php
