<?php
/**
 * Implement hook_menu
 */
function mymodule_menu() {
  $menu['user/%user/add_listing'] = array(
    'title' => 'Add a Listing',
    'description' => 'Click here to create a new listing',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'mymodule_redirect_add_listing',
    'access callback' => 'user_is_logged_in',
  );
  return $menu;
}
 
/**
 * Page callback which redirects to the add listing page
 */
function mymodule_redirect_add_listing() {
  // this takes them to the listing add page and then redirects back to the user page they came from
  drupal_goto('node/add/listing', 'destination=user');
}
?>

<?php
/**
 * Implement hook_menu
 */
function mymodule_menu() {
  $menu['user/%user/add_listing'] = array(
    'title' => 'Add a Listing',
    'description' => 'Click here to create a new listing',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_goto',
    'page arguments' => array('node/add/listing', 'destination=user'),
    'access callback' => 'user_is_logged_in',
  );
  return $menu;
}
?>