In Drupal 5, we've been using the signup_status to grant certificates to user who have a status of Completed.

We have also been using some custom code to insert a link into signup emails which allow a user to confirm their signup without having to log into the site. When the user clicks the Confirm link, they are taken to the site, the confirmation message "Your attendance at %node_title has been confirmed" is displayed, and their signup_status is changed from Registered to Confirmed.

We're looking for someone to complete a port of the signup_certificate sub-module and implement the confirm functionality (in a way that can be contributed back to the project) and thought to start with the module maintainer or a developer who is already familiar with the modules. Ideally, this would be completed by June 14 (with the certificate port being the higher priority).

I can be contacted at http://drupal.org/user/33570/contact to talk about details and what it would take to meet that deadline.