Overview of Microsoft WCF communication technology (Windows Communication Foundation).
WCF is a unified communication framework for distributed .Net applications.
WCF defines a common programming model and unified API for clients and services to send messages between each other.
WCF is the current and future standard for distributed .Net applications.
One of WCFs core concept is ABC which stands for Address, Binding and Contract.
The address defines a service's location. The binding defines how the service can be accessed and the contract defines the service interface.
This common model allows a uniform programming model for distributed applications not only based on web services, but also on message based transports like MSMQ.