I\'m creating a new site and I want the users to be able to use several ways to sign in, basically the users should be able to create a new user on my site OR use Facebook conne
If you're open to spending a few bucks per month the Windows Azure Access Control Service provides this functionality as a drop-in membership provider for ASP.NET. This is also the basis for the new Windows 8 SSO credential flow.
Note that Twitter is not yet supported, however, because Access Control doesn't support OAuth 1.0.