I’ve updated Delink Comment Author to make it compatible with WordPress 2.5. It should also still be compatible with versions prior to 2.5.
This plugin gives you the ability to remove the link a commenter left as their URL without removing the entire comment. A link to do this is added to your new comment e-mail notifications and to the comments list in your admin area.
The download and more information are available on my WordPress Plugins page.
If you have any trouble with this, please open a thread in the WP Support Forums and send me the link.