There is an interesting article on Code Project about using WCF Basic Authentication with SQL Membership Provider.   Obviously, there are much more sophisticated ways of securing WCF services but it is an interesting how-to for getting basic security for WCF up and running.

WCF Basic Authentication with SQL Membership Provider

We will show you how to set up WCF Basic Authentication using the SQL Membership Provider provided by Microsoft.It is highly recommended that you walk through the explanations by looking at the source code as it will help you gain a more solid understanding.You can also run the application on your computer.
We will assume you already know how to setup WCF to run in https, since basic authentication without https would be meaningless because the user name and password would be passed as plain texts in the network.
Topics

We will show you:

• How to setup the database and the Web Site Administration Tool from the .net framework for managing the Users and Roles

• How to setup the WCF Basic Authentication under https and use SQL Membership Provider to validate users and roles

• How to make your WCF service consumable by other other platforms such as Java by making the WSDL a single file

You can also see how to make your service consumable by any technology and also set up error handling here.

Brenton House