On the Professional PHP blog today, there's a quick post concerning a WordPress hack he had to do to fix an annoyance - non-permenant URLs for pingbacks/trackbacks.

I upgraded WordPress to 1.5.2 this weekend. This version fixed some bugs that made it necessary to edit WordPress itself in order to get my BBCode plugin to work.

Unfortunately, this version of WordPress introduced one bug that really annoys me. Pingbacks and Trackbacks aren't using the permalinks, but instead using ugly query string links.

His discovery is that it's related to a cached value in the post.php file - and apparently he was right...