Drupal 6: How to create a new block region above / before comments section

While it is not hard to create a new block region in drupal 6, to create one before comments section
is not as easy to many people. I have managed to add a new block region above the comments, and moved the "similar term" block into it. You can see the result on this page. Here is how I did it:

1. Open clean.info ( clean is the theme name of the theme I use, open your theme-name.info under your theme directory )
below "engine = phptemplate", inset the following line:

regions[above_comments] = Above Comments

"Above Comments" is the name of the new region. Name it whatever you want.

Step 1 is no different from create a normal drupal region. Below is the tricky part:

2. open template.php, add the following code to the end:

function clean_preprocess_node(&$variables, $hook) {
  $variables['above_comments'] = theme('blocks', 'above_comments');
}

3. open node.tpl.php, find the content section, mine is:

<?php print $content ?>

after this section, add:

<?php if ($above_comments): ?>
    <div class="above_comments"><?php print $above_comments ?></div>
<?php endif ?>

4. flush caches, a new block region above comment section have been created.

Note: This region will not show in block list page with highlighted block, but you can assign content blocks to this region and it works fine.