This already exists... look for $g_smtp_host in your config file.

Note that you have to use the phpMailer classes to use this though...

If you're on *nix, you need to have sendmail installed and php just uses that to send the mail wherever it needs to go.

Check out <a href="http://www.php.net/manual/en/ref.mail.php">http://www.php.net/manual/en/ref.mail.php</a> if you need more info

Actually, I just committed code that sets the SMTP system variable when you send a message. This will help if your server is running on windows, but it isn't used on *nix because sendmail should be available there.