Well, I've managed to implement trackbacks by slightly hacking <a href="http://www.movabletype.org/">MovableType</a>'s
<a href="http://www.movabletype.org/trackback/">standalone trackback CGI</a>.
Let me know about any problems you experience with sending me trackbacks, and also
bug me if I forget to send a trackback to you when I link to one of your posts.
<strong>Update:</strong> Robert at Celsius1414 (creator of PHPosxom)
<a href="http://www.celsius1414.com/blog/index.php?entry=/meta/phposxom/iratetrackbacks.txt">linked to this post</a>:
I am planning on creating a trackpack/pingback module for PHPosxom in the near future, but this is a good stopgap.
Matt has also done quite a bit of other tweaks,
including Printable entries.
I plan to write up some "how-to" articles for
<a href="http://www.scotlandsoftware.com/blog/?post=/meta/about_this_blog.html">all the tweaks I've done</a>,
and release the code (after a bit of tidying).
Feel free to subscribe to the feed for the "meta" category here to stay informed!