On the PHPFreaks.com site there's a new post that's a guide for creating a basic development environment on a Debian system (complete with VirtualHosts).

This is just a quick walkthrough describing how to setup a decent development environment allowing the easy setup of multiple sites. It already assumes you have a working Debian or Ubuntu OS installed and configured with PHP, MySql & Apache already running. You will also need to have a working sudo.

They add a group for the web server user (www), change some permissions on the web root directory and edit the base Apache2 "sites" file where the VirtualHosts live. They create a sample PHP file - a phpinfo page - in the directory and add a record to the local hosts file for the new domain. Commands for all of the above are included.