Development of this extension has moved to github. It can be found here: https://github.com/brucem/ezpublish-recaptcha

Feel free to fork and send through pull requests.

Cheers
Bruce

On April 28 2011 changes were made to the reCAPTCHA HTTPS API endpoint URL.  

If you are not using the latest version your users might see SSL certificate warnings when visiting your site.  (However, the CAPTCHA should still load normally, unless the user has restrictive security settings.)