Convergence is a distributed, notary-based SSL certificate verification system. Created by Moxie Marlinspike, the project's goal is to mitigate the dangers associated with untrusthworthy CAs (certificate authorities) and associated potential MITM (Man in the Middle) attacks.
While I do not (yet) contribute code to this project, I do operate a Convergence notary. To get started with Convergence, simply install the browser plugin from the Convervence web site. If you wish to add my notary server to your list of available notaries, click the link below.