EasyPHP is an application that you install on your Windows PC and provides a development enviromment for Apache, mySQL and PHP.
You can download it from http://www.easyphp.org/
When I tried to install it on Windows 7 I came across a number of problems with Apache and mySQL.
This article
http://ryan.rawswift.com/2009/09/20/easyphp-on-64-bit-windows-7-how-to-fix-apache-and-mysql-problem/
solves these problems for me and may by usefull to others.