Xampp (http://www.apachefriends.org/en/xampp.html) is Apache Server, PHP and MySQL in one package. It is easy to install and administer. One question that may arise if you are using a Rich Internet Application programming language such as Adobe Flex or Microsoft Silverlight is where to put your crossdomain.xml (used for Flex and, in certain instances, Silverlight) and/or clientaccesspolicy.xml file(used for Silverlight). Both must be put in the 'htdocs' directory. So if you've installed Xampp on the C: drive you must put your crossdomain.xml/clientaccesspolicy.xml file in the C:\xampp\htdocs directory.

The clientaccesspolicy.xml/crossdomain.xml file is required to enable a Rich Internet Application to access an application under a Web Server, for example, a PHP or Python script. If this file is in the incorrect location or not present at all you will encounter a security error such as the 'System.Security.SecurityException' in Silverlight.