Web Services are business logic components which provide functionality via the Internet using standard protocols such as HTTP.
Web Services uses Simple Object Access Protocol (SOAP) in order to expose the business functionality.SOAP defines a standardized format in XML which can be exchanged between two entities over standard protocols such as HTTP.SOAP is platform independent so the consumer of a Web Service is therefore completely shielded from any implementation details about the platform exposing the Web Service.For the consumer it is simply a black box of send and receive XML over HTTP.So any webservice hosted on windows can also be consumed by UNIX and LINUX platform.