PHP pomoc [e-mail form]

<div id="form_responce_mail" style="display: none;"></div>
<div id="form_div">
<form id="email" name="email" action="sendmail.php" onsubmit="submit_form(this, 'mail', 'sendmail.php');">
<div><label for="name">Name</label>
<input type="text" class="inputbox" size="20" name="name" id="name"/></div><br />
<div><label for="email">Email</label>
<input type="text" class="inputbox" size="20" name="email" id="email" /></div><br />
<div><label for="subject">Subject</label>
<input type="text" class="inputbox" size="20" name="subject" id="subject" /></div><br />
<div><label for="msg">Message</label>
<input type="text" class="inputbox" size="20" name="msg" id="msg" /></div><br />
<div><input class="buttonbox" type="submit" value="Submit form" /></div>
</form>
</div>

<?php

$my_email = " - Email Address Removed for Security -";

if (isset($_POST['action']) && $_POST['action'] == "email"){

$VIRTUAL_REMOTE_HOST = gethostbyaddr( $_SERVER['REMOTE_ADDR'] );
if( $_SERVER['REMOTE_HOST'] ) { }
else {
$_SERVER['REMOTE_HOST'] = "NULL";
}
if( $VIRTUAL_REMOTE_HOST ) { }
else {
$VIRTUAL_REMOTE_HOST = "NULL";
}
}

$mailheader = "From: \"$_POST['name']\" <$_POST['email']>\r\n";
$mailbody = $_POST['msg'];
$mailbody .= "\r\n\r\n\r\n"."------ Technical Information --------\r\n\r\n"."The email has been sent by $_POST['name'] from remote host $_SERVER['REMOTE_HOST'] at ".date("Y-m-d H:i:s")." --> specified hostname $VIRTUAL_REMOTE_HOST. \r\nThe sender's IP Address is $_SERVER['REMOTE_ADDR'] and the sender's \r\nUser-Agent string is $_SERVER['HTTP_USER_AGENT'].";

$email_sent = @mail($my_email, $_POST['subject'], $mailbody, $mailheader);

if ($email_sent) {
echo "Email has been successfully sent";
}
else {
echo "Error occured";
}

}
?>

<?php

$email = $_POST['email'];
$msg =  $_POST['msg'];
$subject = $_POST['subject'];
$name = $_POST['name'];

$chk = @mail($email, 'sub', $msg, "From: $name);

if ($chk)
{
 echo "OK";
}
else
{
 echo "NE VALJA";
}

?>

addslashes()