Creating an OpenID login widget
I need an OpenID login widget like the one on Stackoverflow or Id Selector (which has been discontinued in favor of RPXnow which is a commercial service).
What is the best way to make these? Is there a framework or example implementation anywhere?
Google have a project called Google Identity Toolkit (GITkit) which seems to make OpenID stuff pretty easy. They have their own client library implementation to go with the API service it appears.
This is apparently part of a wider Account Chooser project, which also points to a Janrain implementation called Login Helper, but that seems to be a case of contacting them directly to discuss usage.
Janrain also has a free social login product, which is free up to 2,500 users at the time of writing (April '12). It seems to support many more providers than the Google implementation, although Google say they will be adding more in future.
Google Friend Connect is actually more than what you asked for. It supports other protocols than just OpenID but it supports OpenID too. The widget is pretty easy to use.