Here is the function to add jQuery to the front end of the site. You just need to enqueue the script labeled jquery.
if (!is_admin()) add_action("wp_enqueue_scripts", "default_jquery_enqueue", 11); function default_jquery_enqueue() { wp_enqueue_script('jquery'); }
If for some reason you would like to enqueue a different version you can do so by de-registering jquery and then re-registering it with the version you would like.
if (!is_admin()) add_action("wp_enqueue_scripts", "different_ver_jquery_enqueue", 11); function different_ver_jquery_enqueue() { wp_deregister_script('jquery'); wp_register_script('jquery', "http" . ($_SERVER['SERVER_PORT'] == 443 ? "s" : "") . "://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js", false, null); wp_enqueue_script('jquery'); }
This only changes the front end so the backend is still using the jQuery version it needs.