Custom post type and taxonomy example.

custom-post-types.php

<?php

/* Creating the product listing custom post type
------------------------------------------------------------ */
 
function product_listing() {
  $labels = array(
		'name' => __('Products', 'post type general name'),
		'singular_name' => __('Product', 'post type singular name'),
		'add_new' => _x('Add New', 'Product'),
		'add_new_item' => __('Add New Product'),
		'edit_item' => __('Edit Product'),
		'new_item' => __('New Product'),
		'all_items' => __('All Products'),
		'view_item' => __('View Product'),
		'search_items' => __('Search Products'),
		'not_found' =>  __('No Products found'),
		'not_found_in_trash' => __('No Products found in Trash'), 
		'parent_item_colon' => '',
		'menu_name' => 'Products'
	);
	
	$args = array(
		'labels' => $labels,
		'public' => true,
		'publicly_queryable' => true,
		'show_ui' => true,
		'show_in_menu' => true,
		'query_var' => true,
		'menu_position' => 4,

		'capability_type' => 'post',
		'hierarchical' => false,
		'has_archive' => true,
		'rewrite' => array( 'slug' => 'products', 'with_front' => false ),
		'supports' => array('title', 'editor', 'thumbnail', 'author'),
		'taxonomies' => array('product_category'),
	);
	register_post_type( 'product' , $args );
}

/**
 * Add custom taxonomies for product listing
 */

function product_taxonomies() {

			
	$labels = array (
		'name' => __( 'Product Categories', 'taxonomy general name' ),
		'singluar_name' => __( 'Product Category', 'taxonomy singular name' ),
		'search_items' => __( 'Search Product Category' ),
		'all_items' => __('All Product Categories'),
		'parent_item' => __('Parent Product Category'),
		'parent_item_colon' => __('Parent Product Category:'),
		'edit_item' => __('Edit Product Category'),
		'update_item' => __('Update Product Category'),
		'add_new_item' => __('Add New Product Category'),
		'new_item_name' => __('New Product Category'),
		'menu_name' => __( 'Product Categories' )
	);
	
	register_taxonomy( 'product_category', array('product'), array (
					'labels' => $labels,
					'hierarchical' =>true,
					'show_ui' => true,
					'rewrite' => array( 'slug' => 'product_category'),
					'query_var' => true,
					'show_in_nav_menus' => true,
					'public' => true
			));
}

add_action('init', 'product_listing', 0);
add_action('init', 'product_taxonomies', 10);
?>

functions.php

<?php

/* Include custom post types
------------------------------------------------------------ */

include_once( CHILD_DIR . '/lib/functions/custom-post-types.php' );