Just in case you are studying WCF.. You might want to check out the .NET StockTrader Sample Application. The .NET StockTrader Sample Application is an end-to-end sample application illustrating Windows Communication Foundation and .NET Enterprise Technologies...
Filed under: ASP.NET, Sample, .NET, Web Services, Trading Application, SOA in .NET, SOA, J2EE, WCF, WebSphere, .NET StockTrader Sample Application