I will write series of articles about Web Development Using PHP, this is the part one of those, about activating and installing PHP first. Mac OS X Leopard comes with Apache 2.2 bundle with PHP 5 by default. Beside they still provide option to switch back to PHP4 and also you can actually activate back Apache 1.3 web server. But for PHP, we need to activate it with few steps, which we will cover on this tutorial. We can start the apache web server use the System Preferences » Sharing » Just check the Web Server option.