first time login

i have a registration form in the site. Once the user completes it an email will be send. As usual i mean by default the drupal provides a first time login when the user click the url provided.

After the user clicked an url provided a page is displayed. The url of the page is given in the module called user (file name is user.pages).
So my question is can i redirect the a custom page when the user click the url for the first time..

how to modifiy this default code... in the user.pages

$form['message'] = array('#value' => t('

This is a one-time login for %user_name and will expire on %expiration_date.

Click on this button to login to the site and change your password.

', array('%user_name' => $account->name, '%expiration_date' => format_date($timestamp + $timeout))));
$form['help'] = array('#value' => '

'. t('This login can be used only once.') .'

');
$form['submit'] = array('#type' => 'submit', '#value' => t('Log in'));
$form['#action'] = url("user/reset/$uid/$timestamp/$hashed_pass/login");//this specific line
return $form;

plz looking forward for the suggestion