What is WCF in .Net 3.5

Windows Communication Foundation (WCF)
is Microsoft's programming model for using managed code to build unified Web services and other distributed systems that can talk to each other.
WCF focuses on connecting XML to programs that are built using development languages supported by Microsoft, such as VB.NET and C#.
To support this cross-language communication, WCF uses the extensible Simple Object Access Protocol (SOAP).