/* support custom menus */
add_action( 'init', 'register_my_menus' );
function register_my_menus() {
register_nav_menus(
array(
'menu-nav' => __( 'Navigation Menu' )
// ,
//'menu-2' => __( 'Footer Menu' )
)
);
}

// then in header.php add:

<?php wp_nav_menu( array( 'theme_location' => 'menu-nav' ) ); ?>

http://www.devlounge.net/code/how-to-add-support-for-menus-in-your-wordpress-theme

WordPress enable custom menus

wordpress

PHP