ASP Net LDAP Authentication

I am brand new to ASP Net (but not to programming). I need all the code to implement LDAP Authentication on my web pages. I want to be able to tell who the user is who comes to my site without an additional login screen. All code must be in vb.net . The project needs a default page ([login to view URL]) that will display who the user is. The LDAP Authentication class will provide the user information. I will also need a step by step guide on how to inplement all this in a real application.