Add header above comments (below content)
The goal: add an extra header below the node content and above the comments to more clearly delineate the comments from the content.
Look at http://api.drupal.org/api/4.7/function/node_show
The comments are rendered after the entire node body is emitted. Thus, you could make your node.tpl.php look something like (adpating from bluemarine):
<div class="node<?php if ($sticky) { print " sticky"; } ?>
<?php if ($picture) { print $picture; }?>
<?php if ($page == 0){ ?>
<h2 class="title"><a href="<?php print $node_url?>"><?php print $title?></a></h2>
<?php }; ?>
<span class="submitted"><?php print $submitted?></span>
<span class="taxonomy"><?php print $terms?></span>
<div class="content"><?php print $content?></div>
<?php if ($links) { ?><div class="links">» <?php print $links?></div><?php }; ?>
<?php if ($page && $node->comment && $node->comment_count){ //<-This is the important part ?>
<div><h2>Comments on this post:</h2></div>
<?php }; ?>
</div>The three AND conditions in the last if statement are key:
$page != 0 if the node is being shown as a full page.
$node->comment > 0 if comments are enabled for this page.
$node->comment_count > 0 if the number of comments is greater than zero.