index.php

<?php

$email = $_POST['email'];
$message = $_POST['message'];
mail("kholler@engineyard.com", "Email Subject", $message, "From: $email");

?>

<form method="post" action="index.php">
Email: <input name="email" type="text" />
Message:
<textarea name="message" rows="10" cols="30">
</textarea>
<input type="submit" />
</form>