[wnorris]

Well, the first step would be to look at the OpenID PHP Library at openidenabled.com. Technically, it should certainly be possible, but you may run into a few problems. The first that comes to mind, is what would a user's URL be? The most obvious would be the URL for the member page, but that is of the form "http://site.com/board/member.php?u=12345"... certainly not something all that easy to remember. Moreover, I would seriously think about whether you *should* be running an OpenID server, from a philosophical perspective. For the particular community that I run (and I would imagine this would be the case for most communities), it makes far more sense for my users to bring their own OpenID (from their LiveJournal, perhaps) and I just consume them. If they don't have an existing ID, I will likely point them to somewhere like myopenid.com.