create category using code

require_once 'app/Mage.php';

Mage::app('default'); // Default or your store view name.

//get a new category object

$category = Mage::getModel('catalog/category');

$category->setStoreId(0); // 0 = default/all store view. If you want to save data for a specific store view, replace 0 by Mage::app()->getStore()->getId().

//if update

if ($id) {

  $category->load($id);

}

$general['name'] = "My Category";

$general['path'] = "1/2/23"; // catalog path

$general['description'] = "Great My Category";

$general['meta_title'] = "My Category"; //Page title

$general['meta_keywords'] = "My , Category";

$general['meta_description'] = "Some description to be found by meta search robots. 2";

$general['landing_page'] = ""; //has to be created in advance, here comes id

$general['display_mode'] = "PRODUCTS_AND_PAGE"; //static block and the products are shown on the page

$general['is_active'] = 1;

$general['is_anchor'] = 0;

$general['page_layout'] = 'two_columns_left';

//$general['url_key'] = "cars";//url to be used for this category's page by magento.

//$general['image'] = "cars.jpg";

$category->addData($general);

try {

    $category->save();

    echo "Success! Id: ".$category->getId();

}

catch (Exception $e){

    echo $e->getMessage();

}