OpenID start

[Steven Roussey]

I'm contemplating using OpenID for our site (and other unnamed ones). I have
a few questions:

  1. Where can I find various user interface examples of 
     implementation (client)?
  2. How many (and who are they?) sites use the ID service 
     that have a minimum of 1,000,000 registered users?
  3. Is there a PHP implementation of the client and server?

Thanks,
Steven Roussey
Network54.com