For open-source Web servers, the most popular stack of software is the Apache server, MySQL database, and PHP scripting language. Drawing from their initials, implementations of this on Windows and Linux are known respectively as WAMP and LAMP. XAMPP (free) extends these acronyms, and provides a one-click installation of this stack on Linux, Windows, Mac, or Solaris, along with a handful of other helpful applications and services.
XAMPP is designed to be a development server in a box. There are many other WAMP packages, but XAMPP for Windows is among the most complete and easiest to install. This does however come at the expense of security, so XAMPP is not meant to be used as a production server. The authors at Apache Friends specifically warn against doing so, although if you insist on making your server Web accessible they do provide a nice guide and utility for partially locking it down.
In addition to Apache, MySQL, and PHP, XAMPP includes the phpMyAdmin database administration tool, FileZilla FTP server, Mercury mail server, Perl programming language, and JSP server Tomcat. You can start, stop, and configure these services in the XAMPP control panel which launches from the tray. XAMPP also installs an admin site as the home page of the server. From here you can check the server status and security, launch tools such as phpMyAdmin and Webalizer analytics, and view PHP demos which are particularly useful for beginning developers.
Installing XAMPP required no configuration and completed successfully in less than ten minutes for me. Who says setting up a Web server has to be complicated? Apache Friends maintains a FAQ in case of problems, but most won't need it. XAMPP is perfect for anyone looking to get a full-fledged development server running quickly and effortlessly.