$re = '/^((\+34[\s])|(\(\+34\)[\s]?))?[9|8|7|6][0-9]{2}([0-9]{6}|([\s][0-9]{3}){2}|([\s][0-9]{2}){3})$/';
$str = '(+34) 666 66 66 66';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php