Install mpm itk
On ubuntu mpm itk can be installed from synaptic. Look for the package called apache2-mpm-itk
sudo apt-get install apache2-mpm-itk
Configuration for mpm itk can be done in the file sites-enabled/000-default
$ gksudo gedit /etc/apache2/sites-enabled/000-default
In the VirtualHost *:80 section add this just before the end of the VirtualHost tag
<IfModule mpm_itk_module> AssignUserId your_username your_username </IfModule> </VirtualHost>
Restart apache. Now apache should be running as that username specified in "your_username".
Now this means that even PHP scripts will also run with the same username (unless something like suexec/suphp is changing their user).