Dear Friend,
This link will give you the main differences between remoting, webservices and WCF:-
1). Windows Communication Foundation (WCF) is a technology combined with the features of XML Web Services and .NET Remoting, along with some improvements.
2). .NET Remoting works in a homogenous environment. A consuming application is also required to be in .NET.
Web Services are platform and language independent, and don't care about the consuming application. But it has restrictions of the HTTP protocol. Performance-wise, they are considered slow.
WCF can be hosted under the Windows environment, but it can be utilized by clients of different languages and different platforms.
3). .NET Remoting applications can use the HTTP, TCP, and SMTP protocols.
XML Web Services use SOAP, i.e., XML via HTTP.
WCF, along with all these protocols, can use named pipes and MSMQ as well.
In detail Please read it from this link:-
Web Services Usage
http://www.roseindia.net/webservices/why_webservices.shtml[
^]
Remoting Usage
http://www.c-sharpcorner.com/interviews/answer/1524/[
^]
WCF Usage
he list is endless but to name few of the places where it can be used is
business-to-business (B2B)
business-to-consumer (B2C),
Interoperability with other platforms and technologies
messaging for any kind of communication
Routing
and for all the kind of services that were earlier developed using ASMX, WSE, Web Services, MSMQ, and distributed stack. It also helps in creating the distributed application in a very easy manner that earlier would have involved the usage of two or more distributed technology. These custom solution were earlier not possible to develop in either web services or .NET Remoting. WCF facilitates in building these custom solutions. WCF provides a Uniform programming model to creating distributed applications and has been designed to support Service orientation. for more information, i would advice you to have a look on
http://msdn2.microsoft.com/en-us/library/aa480188.aspx
I hope this will help you out.