In VS.NET, whenever we add a web-reference to a webservice, what happens behind the scenes is that a proxy is created which contains the URL to the webservice.
Now if we need to shift the webservice to a production server, do we have to create the proxy again?. (The IP address of the webservice server would have changed)
Fortunately there is a easy way out. Just right-click on the proxy in VS.NET and change its URL property from 'static' to 'dynamic'. And Voila !!!, VS.NET automatically adds code to the proxy class and web.config. The newly added code in the proxy will first check for a URL key in the web.config and use it to bind to the webservice.
So when we move the webservice to a different server, we just have to change the URL in the web.config file.