Nothing as easy as that. Just get an openID from e.g. pip.verisignlabs.com and add the following 2 lines to your blog header (you'll have to change the marc.seeger part… but you probably have guessed that already ^^:)
< link rel="openid.server"; href="http://pip.verisignlabs.com/server"; mce_href="http://pip.verisignlabs.com/server";>
< link rel="openid.delegate"; href="http://marc.seeger.pip.verisignlabs.com/"; mce_href="http://marc.seeger.pip.verisignlabs.com/";>
(no space after the < and before the "link";)
From now on you can use your blog adress (e.g. marc-seeger.de) as an openID. It will redirect to the openid service of your choice.
I chose pip.verisignlabs.com because I can use my nifty paypal security key that way :D
update: only problem so far:
After mailing with Gary Krall (technical director of PIP) it seems as if they're in the process of evaluating a couple of other approaches which they might implement in a follow-on release. I personally think a whitelist for redirects would be a good Idea :)