the following php code includes pages to the default wordpress feed:


add_action( 'rss2_head', 'theme_do_feed' );

function theme_do_feed()
{
global $wpdb,
$wp_query;

$query_posts_args = array(
'showposts' => -1,
'post_type' => array('post', 'page')
);
query_posts( $query_posts_args );

return;
}