How do I change certain page titles? How do I change certain page titles in Drupal, most notably the create new account, log in, and request new password tab headings?
you can create a module. inside the module you can use the function form_alter to modify the form, and specifically use the function drupal_set_title() to add the title, for example:

create a module with the name "change_title".
add a form_alter function (note that the name of the module is added to the _form_alter name function)

function change_title_form_alter(&amp;$form, &amp;$form_state, $form_id) {

 //dsm($form_id) this function is to know the $form_id

   if ($form_id == 'content_type_node_form') {
       drupal_set_title('this is my new title');
   }

}


note: about how to get the $form_id value, you can use Devel module to use the function dsm($form_id), then the return of this function will show you the $form_id value.