The challenge with securing a shared hosting server is how to secure the website from attack both from the outside and from the inside. [...] This has created a gap that a number of third-party solutions have attempted to fill. One of the oldest of these is suphp, created by Sebastian Marsching.

He works through the whole process - the installation (this is all on a Gentoo linux system), configuring for your Apache install, changing Apache to make it work with suphp and finally some benchmarks and parting comments concerning its use.