<p>Mac OS X ships with apache pre-installed, but the files are in non-standard locations.  This question is a place to collect information about where configuration files live, and how to tweak the apache installation to do things like serve php pages.</p>

Apache Config file is: /private/etc/apache2/httpd.conf
Default DocumentRoot is: /Library/Webserver/Documents/
To enable PHP, at around line 114 (maybe) in the /private/etc/apache2/httpd.conf file is the following line:
```
```
#LoadModule php5_module     libexec/apache2/libphp5.so
```
```
Remove the pound sign to uncomment the line so now it looks like this:
```
```
LoadModule php5_module     libexec/apache2/libphp5.so
```
```
Restart Apache: System Preferences -> Sharing -> Un-check "Web Sharing" and re-check it.
OR
```
```
$ sudo apachectl restart
```
```