Email Address to URL Transformation (EAUT) specification now available! Allows OpenID users to login using their E-mail address, which is converted in to an OpenID URL based on rules specified in an XRDS document attached to the root domain. Seems like a good idea to me.
Sign in with 
OpenID
This sort of stuff is cool, but makes me vaguely sad. Early version of OpenID were nice and conceptually simple. Now people are piling stuff on top, presumably in an effort to make it more useful, but in the process making it harder to understand. That's a shame.
I'm not so sure I'd want to share my email address with other sites, that's why I'm using openid in the first place. And I really don't want email harvesters to have an easy place to find my email address at a predefined location of the root domain.
Thanks for the link, Simon!
@Karl - EAUT doesn't expose your email address to harvesters. You're right that a site that you enter your email address into could have it, but people won't be able to look at your XRDS document and figure out what your email address is.