Index: includes/theme.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/theme.inc,v
retrieving revision 1.542
diff -u -r1.542 theme.inc
--- includes/theme.inc	23 Oct 2009 22:24:11 -0000	1.542
+++ includes/theme.inc	26 Oct 2009 04:29:05 -0000
@@ -1860,7 +1860,27 @@
  * Returns code that emits the 'more help'-link.
  */
 function theme_more_help_link($variables) {
-  return '<div class="more-help-link">' . t('<a href="@link">More help</a>', array('@link' => check_url($variables['url']))) . '</div>';
+  // Prepare the variables.
+  $link = check_url($variables['url']);
+  $id = drupal_html_id('popup-' . $variables['url']);
+  $link_id = drupal_html_id('link-' . $variables['url']);
+
+  // Create a dialog box for the help text.
+  drupal_add_ui('system', 'ui.dialog', '<div id="' . $id . '"></div>', array(
+    'width' => 500,
+    'height' => 400,
+    'title' => t('Help'),
+    'autoOpen' => FALSE,
+  ));
+
+  // Open the dialog box when the link is clicked.
+  drupal_add_ui('system', 'ui.dialog', '#' . $id, 'open', 'click', '#' . $link_id);
+
+  // When the dialog box opens, load the help content.
+  drupal_add_ui('system', 'jquery.load', '#' . $id, $variables['url'].'/dialog', 'dialogopen', '#' . $id);
+
+  // Create the markup.
+  return '<div class="more-help-link">' . t('<a id="@link_id" href="@link">More help</a>', array('@link_id' => $link_id, '@link' => $link)) . '</div>';
 }
 
 /**
Index: modules/help/help.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/help/help.admin.inc,v
retrieving revision 1.11
diff -u -r1.11 help.admin.inc
--- modules/help/help.admin.inc	13 Oct 2009 05:26:57 -0000	1.11
+++ modules/help/help.admin.inc	26 Oct 2009 04:29:05 -0000
@@ -45,6 +45,14 @@
   return $output;
 }
 
+/**
+ * Menu callback; prints the help content and then exits.
+ */
+function help_dialog($name) {
+  echo help_page($name);
+  exit;
+}
+
 function help_links_as_list() {
   $empty_arg = drupal_help_arg();
   $module_info = system_rebuild_module_data();
Index: modules/help/help.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/help/help.module,v
retrieving revision 1.91
diff -u -r1.91 help.module
--- modules/help/help.module	10 Sep 2009 06:32:54 -0000	1.91
+++ modules/help/help.module	26 Oct 2009 04:29:05 -0000
@@ -27,6 +27,14 @@
       'type' => MENU_CALLBACK,
       'file' => 'help.admin.inc',
     );
+    $items['admin/help/' . $module . '/dialog'] = array(
+      'title' => $module,
+      'page callback' => 'help_dialog',
+      'page arguments' => array(2),
+      'access arguments' => array('access administration pages'),
+      'type' => MENU_CALLBACK,
+      'file' => 'help.admin.inc',
+    );
   }
 
   return $items;