Sam Ruby has a good overview of OpenID (wikipedia) and the steps required to start identifying yourself. I personally don’t know much about it but I’m intrigued to learn more after reading some of the recent press about it.
I’ve claimed my identity and this blog on technorati using it’s OpenID interface. Everything worked rather seamlessly. Tomorrow I’ll install the WordPress plugin that will authorize comments via the protocol. I suspect it’ll work as expected.
Decentralization is nice, there’s no reason you can’t install something like phpMyID and host your identity on a server of your choosing instead of storing it centrally (on a site like myopenid.com). I’ve yet to do it myself but Sam’s instructions are simple enough.
OpenID is increasingly gaining adoption amongst large sites, with organizations like Technorati both acting as a Relying Party and as a Provider as well as Wikipedia announcing that they will support OpenID