You do this in your Config\routes.php file. Set the Router params to write the URL as you need. Do not edit your htaccess files or it can/will break CakePHP routing.
Router::connect('/:controller/:param1/:param2', array('action' => 'index'), array('param1' => '[a-zA-Z0-9]+', 'param2' => '[a-zA-Z0-9]+'));
This should send all requestes to any controller to the index function of that controller and pass params 1 and 2. Of course, this can be heavily customized. I would strongly suggest you read about routing in the documentation and never alter htaccess unless you have to.
http://book.cakephp.org/2.0/en/development/routing.html#routes-configuration
