silverlight wcf and custom username and password

I have a silverlight application. I have many wcf files hosted by iis 6. I have a custom username/password store.

What is the best way to secure the wcf?

Also I will have a third party desktop app call this WCF as we开发者_如何学Pythonll.

see followng link http://blogs.infosupport.com/blogs/alexb/archive/2009/10/02/silverlight-3-securing-your-wcf-service-with-a-custom-username-and-password-authentication-mechanism.aspx

Here is an example using a custom validator.