What are webservices?
Broadly speaking "Web Services" are programs that let one computer system talk to another computer system over the internet. For example, you might want to enter customer details into a office computer system and have those customer details be checked on an online 'address checking' website or something similar.
Today, Web Services are self-contained, self-described, component applications that can be published, located, and invoked across the Web. Web Services provide a standard means of interoperating between different software applications running on a variety of platforms. eXtensible Markup Language (XML) provides the extensibility and language neutrality that is the key for standards-based interoperability of Web Services. They perform functions that can include anything from simple query responses to complex business processes. Once a Web Service is deployed, other applications can discover and invoke it. At present, Web Services require human interaction for identification and implementation.
A web service has list of methods and procedures that can be used by any of the applications irrespective of the programming languages, OS, hardware used to develop them. Any type of applications can access the functionality provided by the web service and such functionality is called web methods or web APIs.