Stuff

$previous_database = db_set_active('seperate_db')db_set_active($previous_database);function YOURMODULENAME_user($op, &$edit, &$account, $category = NULL) {  if ($op == 'form' && $category == 'account') {    $form['comment_settings'] = array(      '#type' => 'fieldset',      '#title' => t('Comment settings'),      '#collapsible' => TRUE,      '#weight' => 4);    $form['comment_settings']['signature'] = array(      '#type' => 'textarea',      '#title' => t('Signature'),      '#default_value' => $edit['signature'],      '#description' => t('Your signature will be publicly displayed at the end of your comments.'));    return $form;  } else if ($op == "insert") {    // MAKE VALUES IN BOTH  } else if ($op == "delete") {    // KILL VALUES IN BOTH  } elseif ($op == "update"){    // UPDATE VALUES IN BOTH  }} db_set_active();