I really like the idea behind OpenID, and I already have an account at Weblogs SL. Of course, my WordPress.com also was a valid OpenID provider. Moroever, my isilanes.org site (and before that my EHU page) was turned into an OpenID provider by adding the following lines (extra blank added before "link", to make text visible):
< link rel="openid.server" href="http://openid.blogs.es/index.php/serve" />
< link rel="openid.delegate" href="http://openid.blogs.es/isilanes" />
But I was not completely happy with that. I when signing a comment in a blog (for example) with my WP blog URL, my nickname would appear as "handyfloss" (the name of the blog), not "isilanes" (my nick). If I used the Weblog URL (or that of www.ehu.es/isilanes), my nick would be "isilanes", but clicking on my nick would take the reader to that URL, instead of to my blog.
With this WordPress.org blog these issues are gone. I have installed the Yadis plugin, and now I can sign with the "isilanes" nick, and give a link to this blog.
The configuration of the plugin is really simple: go to Options->Yadis->Add New Service, and select "Other...". You will be asked for two data: "OpenID Server" and "OpenID Delegate" (both provided by your OpenID account, with Weblog or whoever). Fill in the requests, click "submit", and you're done!