apache2-mpm-itk (just mpm-itk for short) is an MPM (Multi-Processing Module) for the Apache 2 web server. mpm-itk allows you to run each of your vhost under a separate uid and gid — in short, the scripts and configuration files for one vhost no longer have to be readable for all the other vhosts.
Apache2 installation with PHP support
Install apache2 with PHP4 or PHP5 support in debian etch
#aptitude install apache2
This will complete the installation
Now you need to install php4 or php5 for apache2 server