A web server is software that serves web pages in response to requests from web browsers. A web server is sometimes called an HTTP server.
Suppose you use IIS to develop web applications. The default name of your web server is the name of your computer. You can change the server name by changing the name of your computer. If your computer has no name, the server uses the word localhost.
The server name corresponds to the server’s root folder, which (on a Windows computer) is most likely C:\Inetpub\wwwroot. You can open any web page stored in the root folder by entering the following URL in a browser running on your computer:Popular web servers are JSP, PHP, ASP, or ASP.NET, etc.
Which server technology you choose also depends on the application server you plan to use for your web application. An application server is software that helps a web server process web pages containing server-side scripts or tags. For example, if you have ColdFusion MX 7 Server, you can choose ColdFusion as your server technology. If you have access to a server running Microsoft Internet Information Server 5 (IIS) with the .NET Framework, you can choose ASP.NET. PHP is an option if you have access to a web server with a PHP application server; JSP is an option if you have access to a web server with a JSP application server.
more detailes, please visit:
http://msdn.microsoft.com/asp.net
http://www.php.net
http://msdn.microsoft.com/java.sun.com/products/jsp