How to disable link on a node title?
The code that makes that happen is in node.tpl.php:

&lt;?php if (!$page): ?&gt;
&lt;h2&lt;?php print $title_attributes; ?&gt;&gt;
  &lt;a href="&lt;?php print $node_url; ?&gt;"&gt;
    &lt;?php print $title; ?&gt;
  &lt;/a&gt;
&lt;/h2&gt;
&lt;?php endif; ?&gt;


So to override it, you just need to re-create node.tpl.php somewhere in your theme's folder, remove the &lt;a&gt; tag surrounding the title, and clear Drupal's caches. Then you won't get links on title for node teasers any more.

If this is too 'all-encompassing' and you just want to do it for a specific content type then as well as copying the original (unchanged) node.tpl.php into your theme's folder, create another one called, for example, node--article.tpl.php (for the article content type), and make the alterations in there instead.