You've been kicked in the nuts: signing up in iPhone apps
iphone.broadersheet.com
iphone.broadersheet.com
No, the service can't "pull your email info from it" -- OpenID provides no information about an authenticated user to the service beyond "yes, they are that identifier".
You don't need to type in a long URL to login using OpenID. If you have a domain you can use it to delegate the OpenID provider to use for logins. So you need something like openid.mydomain.com and a username and login. One set of authentication information to remember instead of different ones for every website or application you use.
You wouldn't want to use Webkit to implement OpenID on the iPhone anyway. You would want to integrate it into your application so that was a seamless process.