An online guide to WCF
The atomic unit of any service oriented architecture [SOA] is a service. The key technology to develop services in Windows is called the Windows Communication Foundation. This is a part of the .NET Framework 3.0 which released on November 6th, 2006.
Following is an online guide that should help you get familiar with this exciting new technology called WCF -
GET - Installers
LEARN - eLearning
READ - Documentation
USE - Labs