FirePHP can nicely complement the built-in tools available when using Zend Server and can be easily made available to all provisioned sites. This tutorial illustrates how to setup FirePHP 1.0 for all virtual hosts on a Zend Server AMI on Amazon EC2.
He steps you through the process of getting FirePHP installed and working in your browser as well as pulling the "firephp.phar" file in on the Zend Server side. Configuration is pretty simple - the lines for the Apache config are included and the JSON needed to make the credentials for FirePHP are too. A simple test script is created and an auth key is set and you should be up and running.