Web service is a common class that exists on the Internet. As long as you need it according to standards, you can call it when you need it ----- My understanding
Learning Web Service To understand a few concepts
1) XML and XML Schema: XML is the basic expression of data, that is, don't use other databases, all data is expressed in XML, many advantages don't have to say more. XML Schema is a definition of the type of elements and attributes. Is the definition of "data type". XML provides more than 40 types of definitions.
2) WSDL: It is a description of the Web Service, describing features, parameter methods, and the like. I don't know how to call these.
3) UDDI: This thing is about the storage of Web Service. Help you find Web Service
4) SOAP: is the transfer information format.
Many things can write Web Service, but you should choose .NET because it gives you a comprehensive support.
