You want to turn your blog into an OpenID server so you can login to sites accepting OpenID with your own OpenID url.One nice advantage of this is that if you're already logged into your blog you don't have to provide a username and password anymore.
You install the OpenID plugin, configure it as a server, but you run php 5.3 and the server part of this plugin doesn't work with PHP 5.3.
Download my patch ( for OpenId 3.3.2 plugin ) :OpenID Server php 5.3 patch-0.1 (907 bytes)
Copy to wp-content/plugins and run:
patch < openid-server-php.5.3.diff
For the lazy ones here's a version of the OpenID plugin that's already patched: OpenID Server php 5.3 Patched Plugin-3.3.2 - 0.1 (402.61 KB)
Just install it instead of the original plugin.