Web Service Authentication in a C # Web Application ie Details on Digests and Basic Authentication

Details of all web service authentication methods and how to apply them? ie How to apply basic and digest authentication in a C # web application.

Optional: I am creating a web service and want to deploy it to IIS 5.0. To authenticate a user, I want to use digest validation. How it's done? Authentication should contain some through which the user is authenticated inside the database to authenticate and then if a valid user then returns success or failure ...