使用C＃从ASP.Net MVC访问Active Directory

I need to access Active Directory to get information about groups that customers belong to. The project I have is an ASP.Net MVC application using C#. I've never programmed against Active Directory before, and need some advice on what the best way to get started is, what security model to use to access the information, and maybe point me to some good tutorials.I need to access Active Directory to get inform