Custom authentication at the URL level, use ISAPI still with .NET or is there a new way

public class AuthModule : IHttpModule
{
    public void Init(HttpApplication context)
    {
        context.AuthenticateRequest += OnAuthenticateRequest;
        context.AuthorizeRequest += OnAuthorizeRequest;
    }

    private static void OnAuthenticateRequest(object sender, EventArgs e)
    {
        // authenticate the user here...
        // (note that the sender argument is an HttpApplication instance)
    }

    private static void OnAuthorizeRequest(object sender, EventArgs e)
    {
        // ...then authorize their attempted action here, if needed
    }
}