Josh Carter has developed a [2] plugin for Movable Type that on it's own didn't work, but in conjunction with the one provided with the release, seems to be working. I had to manually enter the keys into the Recaptcha.pl file, because it wasn't working when the keys were entered on the plugin screen alone. This seems so absurd to me, but there you have it. Don't follow Josh's instructions for adding code to the comments.pm file when installing the plugin. They don't work with this new version of MT.

You need to add the code to the comment-form template for the captcha image to show up, and remove the reference to the div id.

Look for the following line of code:

<div id="comments-open-captcha"> </div>

Remove the id and leave a plain div. Insert the code following between the div elements:

<$MTRecaptchaBox$>

Save and rebuild the site. Captchas should now be working. Good luck.

Update: (Sept 9) Josh has [3] instructions for getting Movable Type's version of ReCaptcha to work. It seems to work with a new blog, but didn't appear on this one and I went back to using both.