This is a simple php mail() function script
Code:
<?php
$to = "someone@example.com";
$subject = "Test mail";
$message = "Hello! This is a simple email message.";
$from = "someonelse@example.com";
$headers = "From: $from";
mail($to,$subject,$message,$headers);
echo "Mail Sent.";
?>
I guess you just stick it in as a script that runs when the page is visited. Not sure about the session cookie thing though...