Windows communication foundation is a unified programming framework to create secure, reliable, transacted, service oriented distributed applications.  WCF is part of WinFX, the next generation programming model for windows vista and beyond. WCF is written from ground up and brings together all the features, functionality and more of today’s Microsoft stack for creating distributed applications (ASMX, WSE, MSMQ, Enterprise Services (COM+) and .Net Remoting).

WCF is designed to accomplish following goals

v  Improve Productivity

o   Learning one programming model for creating distributed application.

o   Write less code or no code, attribute based programming

o   WCF is an extension of .Net 2005, leveraging the power of VS2005 IDE and .Net framework.

v  Interoperability

o   Ability to interoperate with distributed application on other platforms using WS* specifications

o   Ability to interoperation with distributed applications on MS platform  build with today’s MS distributed technology ( ASMS, MSMQ, ES …)

v  Service Orientation

o   Supporting all tenets of SOA Applications

§  Boundaries are Explicit – Separating out implementation from published interfaces using attributes.

§  Services are Autonomous – by specifying the ABCs (Address, Binding and Contract) in configuration files we can achieve versioning and location transparency for a WCF application

§  Services share schema and contract, not classes – WCF application can publish Contract schemas, Data Schemas and Message Schema by classifying your class, methods by attributes.

§  Service compatibility is determined based on policy – Service policy statements are automatically created based on configuration, class attributes and method signatures.

WinFX ships as a core part of Windows Vista, there is also a down level support for Windows XP and Windows 2003 server.

Get more information -
http://www.microsoft.com/windowsvista/default.aspx
http://windowscommunication.net