Snippet to hide the editing of one vocab
You will need to create a custom module with:

Drupal 6:

/**
 * implements hook_form_alter()
 */
MYMODULE_form_alter($form, $form_state, $form_id) {
  if ($form_id == 'type_node_form') {

    global $user;

    // Check to see if $user has does not have the administrator role.
    if (!in_array('administrator', array_values($user-&gt;roles))) {
      //to turn all vocabularies off 
      $form['taxonomy']['#access'] = FALSE;

      //turn off a single vocabulary *BELOW*
      //if you select 'tags' from your vocabulary settings
      if(issset($form['taxonomy']['tags']) {
        $form['taxonomy']['tags']['vid'] = FALSE;
      }
      else {
        //if you do not selet 'tags' from your vocabulary settings
        $form['taxonomy']['vid'] = FALSE;   
      }
    } 
  }
}


So there is 3 options, depending how your vocabularies are setup.  You must subsitute 'vid' for the vocabulary id.

Drupal 7:

inside hook_form_alter() like

if ($form_id == 'type_node_form') {

  global $user;

  // Check to see if $user has does not have the administrator role.
  if (!in_array('administrator', array_values($user-&gt;roles))) {
    $form['name_of_field']['#access'] = FALSE;
  }
}