The Monkeysphere Project XUL Extension
The Monkeysphere project's goal is to extend OpenPGP's web of trust to new areas of the Internet to help us securely identify each other while we work online.
This Mozilla/Firefox/Iceweasel XUL extension, along with a Monkeysphere validation agent, will allow you to validate https web sites that have been put on the OpenPGP web of trust.