Removes 'Private:' and 'Protected' from the start of post titles.

functions.php

<?php

function nacin_remove_private_protected_from_titles( $format ) {
	return '%s';
}
add_filter( 'protected_title_format', 'nacin_remove_private_protected_from_titles' );
add_filter( 'private_title_format',   'nacin_remove_private_protected_from_titles' );