I was chatting with nugget and a couple of other people regarding phpBB and its associated support for OpenID. I googled for "phpbb openid" and the first hit pointed to phpbbopenid.com. Sure enough, this domain is itself an instance of a phpBB that has discussion forums regarding OpenID support. I think it's the home page for an addon package for phpBB that offers OpenID, but the details of that are buried somewhere in one of the forums. You'd think they would add a big "Download" button on the front page or something.
The big irony here is that the "Login" button on this board, while sporting a vaguely OpenID-like image, goes to a page that prompts for only a username and password, without an OpenID login option at all!