Best OpenId API for ASP.NET MVC application

Solution 1:

We use the excellent DotNetOpenId library here on Stack Overflow:

http://code.google.com/p/dotnetopenid/

now moved to:

http://www.dotnetopenauth.net/

Our original login UI was provided by ID Selector, but we've since rolled our own minimalist version.

Solution 2:

I'll second the recommendation for DotNetOpenId and add a recommendation for openid-selector (open source version of idselector)