The term webservices describe a standardized way of integrating web-based applications using the XML,SOAP,WSDL and UDDI open standards over an internet protocol backbone.
XML is used to tag the data,SOAP is used to transfer the data,WSDL is used for describing the services available and UDDI is used for listing what services are available.
Web Services used primarily as a means for business to communicate with each other and with clients.Web Services allows organizations to communicate data without intimate knowledge of each other's IT systems behind the firewall.
Unlike traditional client/server model,such as webServer/web page System, Web services don't provide the user with a GUI.Web Services instead share business,data and processes through a programatic interface acrros a network.The applications interface, not the users.Developers then can add the web services to the GUI(such as an webpage or an excecutable program) to offer specific functionality to users.
Web services allow different applications from different sources to communicate with each other without time-consuming custom coding and because all communication is in XML,web services are not tied to any operating system or progamming langauage.For eg Java can talk with Perl, windows application can talk with Unix applications.
Web services don't require the use of browser or HTML.
Web Services are sometimes called application services.