add_action('wp_dashboard_setup', 'my_dashboard_widgets');
function my_dashboard_widgets() {
     global $wp_meta_boxes;
     // remove unnecessary widgets
     // var_dump( $wp_meta_boxes['dashboard'] ); // use to get all the widget IDs
     unset(
          $wp_meta_boxes['dashboard']['normal']['core']['dashboard_plugins'],
          $wp_meta_boxes['dashboard']['side']['core']['dashboard_secondary'],
          $wp_meta_boxes['dashboard']['side']['core']['dashboard_primary']
     );
     // add a custom dashboard widget
     wp_add_dashboard_widget( 'dashboard_custom_feed', 'News from yoursite', 'dashboard_custom_feed_output' ); //add new RSS feed output
}
function dashboard_custom_feed_output() {
     echo '<div class="rss-widget">';
     wp_widget_rss_output(array(
          'url' => 'http://www.yoursite.com/feed',
          'title' => 'What\'s up at yoursite',
          'items' => 2,
          'show_summary' => 1,
          'show_author' => 0,
          'show_date' => 1 
     ));
     echo "</div>";
}

http://smashingmagazine.com

Taken from an article of http://smashingmagazine.com

Removing feeds from Wordpress and add another one

wordpress

PHP