If you want to hide authoring information and the other fieldsets on new/edit node pages, add something like this to a module. It seems to work, but please reply if anyone's got a better solution.
You'll need to change 'news_article_node_form' to e.g. 'page_node_form' or whatever your node type is. Alternatively if you want it for all node types.
<?php
// Implementation of hook_form_alter
function news_article_form_alter($form_id, &$form) {
if ($form_id == 'news_article_node_form') {
// We're going to hide various fields by setting default values for them
$form['author']['#type'] = 'value';
$form['author']['name'] = array('#type'=>'value', '#value'=>$form['author']['name']['#default_value']);
$form['author']['date'] = array('#type'=>'value', '#value'=>$form['author']['date']['#default_value']);
$form['options']['#type'] = 'value';
$form['options']['status'] = array('#type'=>'value', '#value'=>$form['options']['status']['#default_value']);
$form['options']['moderate'] = array('#type'=>'value', '#value'=>$form['options']['moderate']['#default_value']);
$form['options']['promote'] = array('#type'=>'value', '#value'=>$form['options']['promote']['#default_value']);
$form['options']['sticky'] = array('#type'=>'value', '#value'=>$form['options']['sticky']['#default_value']);
$form['options']['revisions'] = array('#type'=>'value', '#value'=>$form['options']['revisions']['#default_value']);