WP Calais Auto Tagger has been updated to version 1.3 and works on new versions of WordPress again. This is a complete rewrite of the tagging interface to hopefully make the plugin more resilient — it’s been breaking when WordPress releases new versions too often for my liking. Now it replaces the WordPress tag interface entirely with its own, which has the same functionality (add and remove tags) as well as the ability to suggest tags based on the post content.
Update: v1.3.1 fixes bugs with the visual editor and scheduled posts.
Leave a comment if you run into any bugs. I hope to fix up the archive tagger plugin soon as well.