Google's IDP is now live. You can try it on Plaxo, ZoHo, & Buxfer and hopefully more RPs to come soon. Here is the blog post with more details, including information on how RPs can sign up to use the service:<br>
<div><br></div><div><a href="http://google-code-updates.blogspot.com/2008/10/google-moves-towards-single-sign-on.html">http://google-code-updates.blogspot.com/2008/10/google-moves-towards-single-sign-on.html</a><br></div>
<div><br></div><div>And yes, it does allow RPs to request a user's E-mail address via AX as an option. I'll let Joseph Smarr from Plaxo respond with details on how they are using that feature to further simplify the signup flow for Plaxo.</div>
<div><br></div><div>Eric Sachs</div><div>Product Manager, Google Security</div>