How to Hide the "WP-Grooveshark Settings" Admin Menu

function plt_hide_wp_grooveshark_menus() {
	//Hide the "Settings → WP-Grooveshark Settings" menu.
	remove_submenu_page('options-general.php', 'wp-grooveshark/wp-grooveshark.php');
}

add_action('admin_menu', 'plt_hide_wp_grooveshark_menus', 11);

Where do I put this code?