add_filter( 'wp_nav_menu_items', 'add_skype_button_second_nav_menu', 10, 2 );
/**
* @author Brad Dalton - WP Sites
* @example http://wpsites.net/web-design/add-phone-number-genesis/
*/
function add_skype_button_second_nav_menu( $menu, stdClass $args ){
        
       
        if ( 'secondary' != $args->theme_location )
        	return $menu;
        
               if( genesis_get_option( 'nav_extras' ) )
                return $menu;
        
        $menu .= sprintf( '<li class="right ph-num">%s</li>', __( '<a href="skype:username007">Skype</a>' ) );
        
        
        return $menu;
        
}