Drupal: Horizontal Menu

Question

I'm trying to programmatically create the custom horizontal menu for my custom module, but I'm having a lot of trouble.

I want to make a horizontal menu like this :

This is my code so far, but it only displays on the main left vertical sidebar with everything else (this is the pre-packaged Garland theme):

/* hook_menu implementation for my 'lab' custom module */
function lab_menu() { 
  $items = array(); 
  $items['lab/admin'] = array( 
    'title' => 'LAB Admin',
    'page callback' => 'some_method',
    'access arguments' => array('access content'),
    'access callback' => 'user_access',
    'type' => MENU_NORMAL_ITEM,
   );      
  /* should appear as a 'tabbed' horizontal method */ 
  $items['lab/admin/appoint'] = array(
    'title' => 'LAB: Appointment',
    'page callback' => 'some_method',
    'page arguments' => array(1),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_NORMAL_ITEM,
  );
  $items['lab/admin/reviewers'] = array(
    'title' => 'Reviewer\'s Link',
    'page callback' => 'some_method',
    'page arguments' => array(1),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_NORMAL_ITEM,
  );
  return $items;
}