Blogger is now supporting OpenID.
Not to be outdone, this blog is as well. If you have an account at Livejournal, WordPress.com, AOL/AIM, or Typepad, you’ve got an OpenID. There are also OpenID providers you can sign up with, or you can host your own OpenID. Let me know if you have any issues. No log-in is required for comments, so you won’t see the form unless you register.
I recommend hosting it yourself, because your host may be less reliable than a top tier provider, but at least you have some control over it. At the very least, you should delegate a domain you control, such as your blog, as your identity URL, so you can switch providers if necessary. Here’s an (untested) Open ID delegation plugin for WordPress to make it even easier.