In a new post today Stuart Herbert asks the question "is it possible to secure a shared server with PHP and FastCGI installed on it?" His answer follows...

The challenge with securing a shared hosting server is how to secure the website from attack both from the outside and from the inside. PHP has built-in features to help, but ultimately it's the wrong place to address the problem. [...] Before we can look at performance, the first question is: how exactly do we get PHP and FastCGI running as different users on the one web server in the first place?

He follows through on this, giving a little mini-tutorial on getting the environment installed on an Apache web server. He includes some benchmarks on the difference between using the Apache 1.3.x series and Apache 2 (generated using the ab benchmarking tool).