win主机，如何来配置邮件发送的功能？

注册用户后都是提示：
warning: mail() [function.mail]: Failed to connect to mailserver at "localhost" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set() in F:\www\includes\mail.inc on line 193.
Unable to send e-mail. Please contact the site admin, if the problem persists.

该如何设置才是正确的？