Вот рабочий код. Он использует Pear Mail package.
<?php require_once "Mail.php"; $from = "<from.gmail.com>"; $to = "<to.yahoo.com>"; $subject = "Hi!"; $body = "Hi,\n\nHow are you?"; $host = "ssl://smtp.gmail.com"; $port = "465"; $username = "<myaccount.gmail.com>"; $password = "password"; $headers = array (''From'' => $from, ''To'' => $to, ''Subject'' => $subject); $smtp = Mail::factory(''smtp'', array (''host'' => $host, ''port'' => $port, ''auth'' => true, ''username'' => $username, ''password'' => $password)); $mail = $smtp->send($to, $headers, $body); if (PEAR::isError($mail)) { echo("<p>" . $mail->getMessage() . "</p>"); } else { echo("<p>Сообщение успешно отправлено!</p>"); } ?>