Does anyone know of a way to include additional fields onto the registration form for Wordpress where those new field values could be included in the email generated when a new user is set up?

I've tried using Theme My Login but running into issues where it doesn't appear to file the fields. I'm using the following:

function tml_new_user_registered( $user_id ) {
	if ( isset( $_POST['user_first'] ) )
		update_user_meta( $user_id, 'user_first', $_POST['user_first'] );
	if ( isset( $_POST['user_last'] ) )
		update_user_meta( $user_id, 'user_last', $_POST['user_last'] );
	if ( isset( $_POST['user_company'] ) )
		update_user_meta( $user_id, 'user_company', $_POST['user_company'] );
	if ( isset( $_POST['user_address'] ) )
		update_user_meta( $user_id, 'user_address', $_POST['user_address'] );
	if ( isset( $_POST['user_phone'] ) )
		update_user_meta( $user_id, 'user_phone', $_POST['user_phone'] );
	if ( isset( $_POST['user_fax'] ) )
		update_user_meta( $user_id, 'user_fax', $_POST['user_fax'] );
}
add_action( 'tml_new_user_registered', 'tml_new_user_registered' );
?>