Personal Web Sharing
From Mac Guides
Mac OS X
Apache has been the most popular web server on the Internet since April of 1996. The November 2005 Netcraft Web Server Survey found that more than 70% of the web sites on the Internet are using Apache, thus making it more widely used than all other web servers combined.
Turning on Web sharing in OS X is as easy as clicking a check box in the Sharing System Preferences pane. Files shared by OS X Web sharing exist in one of two types of locations — the system-wide site and user-specific sites.
Files at /Library/WebServer/Documents will, by default, be shared as the root Web site when Web sharing is turned on. These files can be accessed at http://localhost/ or http://<yourIPaddress>.
Files at ~/Sites, or in your home folder's Sites folder, are considered your user-specific site files. Each user by default has one of these folders. Each user's site can be accessed at http://<yourIPaddress/~(shortusername).
Apache is extremely powerful and customizable. This customization is a bit easier in Mac OS X Server, which includes GUI tools for configuring Apache. The client version of OS X runs exactly the same Apache server, but configuration must be done completely through the editing of a text configuration file at /etc/httpd/httpd.conf.
See the Working with PHP and MySQL guide.