I have a similar problem. I just started blogging a few months ago and installed WP 2.0.x version. I was never able to display pingbacks or trackbacks on my blog.
I read in this support forum that upgrading to 2.1 will solve the problem. I have since upgraded - but I still do not see any pingbacks or trackbacks to my blog.
the blog address is http://www.iqi-sm.com/blog/
I do have the header information in place, the xmlrpc.php file and `<!--
<?php trackback_rdf(); ?>
-->` in my comments.php file.
I also have the relevant boxes checked in the discussion options. I do have the email required option checked.
This not working is driving me up the wall. Please help.