webservices

1. http://msdn.microsoft.com/en-us/library/ms972326.aspx
2. http://msdn.microsoft.com/en-us/library/t745kdsh.aspx

  By using Web services, your application can publish its function or message to the rest of the world.Web services use XML to code  and to decode data, and SOAP to transport it (using open protocols).

Web Services have Two Types of Uses

Reusable application-components.

There are things applications need very often. So why make these over and over again?

Web services can offer application-components like: currency conversion, weather reports, or even language translation as services.

Connect existing software.

Web services can help to solve the interoperability problem by giving different applications a way to link their data.

With Web services you can exchange data between different applications and different platforms.

Difference :-

Web Application: In software engineering, a Web application or webapp is an application that is accessed via Web browser over a network such as the Internet or an intranet. It is also a computer software application that is coded in a browser-supported language (such as HTML, ASP, PHP, Perl, Python etc.) and reliant on a common web browser to render the application executable.

Web applications are popular due to the ubiquity of a client, sometimes called a thin client. The ability to update and maintain Web applications without distributing and installing software on potentially thousands of client computers is a key reason for their popularity. Common Web applications include Webmail, online retail sales, online auctions, wikis, discussion boards, Weblogs, MMORPGs and many other functions.

Windows Application: A program that is written to run under Microsoft's Windows operating system. Such applications typically run under all 32-bit versions of Windows, but earlier applications might also run under the 16-bit versions (Windows 3.x) as well.