If you want to use jQuery JavaScript library in your WordPress theme, the best choice is to load the version hosted on Google servers instead of the local one shipped by default with WordPress.

To load jQuery from Google you have to edit the functions.php file of your theme adding these lines of code:

if( !is_admin()){
   wp_deregister_script('jquery');
   wp_register_script('jquery', ("http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"), false, '1.3.2');
   wp_enqueue_script('jquery');
}

Include jQuery from Google in WordPress is a post from: WordPress World