I've got an email sending page:

Code:
<h1>Send a message to someone's email:</h1>
<form action="post.php" method="POST">
From: <input type="text" name="sender" value="" /><br />
To: <input type="text" name="receiver" value="" /><br />
Subject: <input type="text" name="subject" value="" /><br />
Message: <input type="text" name="message" value="" /><br />
<input type="submit" value="submit" />
</form>
Code:
<?php
$from = $_POST['sender'];
$to = $_POST['receiver'];
$msg = $_POST['message'];
$subj = $_POST['subject'];

mail($to,$subj,$msg);
echo "Mail Sent. "."From: ".$from." To: ".$to;

?>
The only thing I've difficulty in is the config of php.ini:
I am not sure about my ISP and
I'm using XAMPP for testing
How could I set it up for sending emails on webpages?
Code:
[mail function]
; For Win32 only.
; http://php.net/smtp
SMTP = localhost
; http://php.net/smtp-port
smtp_port = 25

; For Win32 only.
; http://php.net/sendmail-from
;sendmail_from = postmaster@localhost