如何在asp.net mvc3项目中开始使用openID？

I want to have authentication mechanism for my site (in asp.net mvc3), first option openID another option via my site. I don't know how to start with dotnetopenid, because it does not have a good document or some guidance to start with it. Is there any visual document or any useful step by step resource for it. The other question: I want to have google and yahoo openID authentication, is there any difference for using both of them?!I want to have authentication mechanism for my