{            return par1+par2;

        }

 }

    public class BenefitCalculator : IBenefitCalculator    {

         public float CalculateRatio(int par)

        {            return par*10/100;

        }

 }

One of the main conceptions behind WCF is the separation between code (that is for programmers) and configuration of behavior (that is for administrators)Here all what I did is create two interfaces m and implemented them, all what I had to do in this dll library is add the attribute [ServiceContract()] for the interface and  [OperationContract] for the exposed signature.I did another project which is the host for my WCF services, quite simple, a web form that has two buttons, for starting services and stopping them.Code for doing this is quite straightforward internal static ServiceHost myCalculatorServiceHost = null;         internal static void StartCalculatorService()         {            Uri baseAddress = new Uri(“http://localhost:8080/calculator”);            myCalculatorServiceHost = new ServiceHost(typeof(WCFCalculators.Calculator), baseAddress);            myCalculatorServiceHost.Open();        }It would be better to keep the service address in the config file, so think about doing it.That’s all about code, now we have to define the End Points ABC (Address is already defined in the code, so we still have to define Binding and Contract)I used basic basic http binding, changing it to secured doesn’t really need a lot to do, just a small configuration change, Here is the binding I usedNow as I have my services ready, my host as well, I go for orchestration, that was the simplest part, I just added a new workflow library, I added WebServiceInputActivity/ WebServiceInputActivity which says that the input to my workflow will be a web service call, I had to set the activating activity to true, to tell the workflow to start on the webservice call, Then the composition of the two other services was quite graphic, I didn’t touch to any code, I just had to right click on the workflow project and choose publish as asmx webservice.AND THATS ALL!!!To run the solution, u should start the host project, start the services, then call the orchestration service. I hope this could illustrate a little bit of goodness about .net 3.0 ! i ll try in future demos to involve transaction, thats where fun comes in :Dps:forgot to tell that WF xoml is an xml representation of the WF and can be exported as BPEL. Source Code in C#