On the Binary Tides blog there's a new setup tutorial showing how to get Apache 2.3 and PHP FPM up and running with mod_proxy FCGI on Ubuntu (13.10, more specifically).
With the arrival of mod_proxy_fcgi Apache finally gets the ability to neatly talk to external fastcgi process managers making it more efficient at the task. Delegating php requests to external fpm servers greatly reduces the load on web servers like apache resulting into efficient utilisation of machine resources and faster processing speed for users on the other end. Along with all that, php fpm can run opcode caching engines like apc in a very stable manner.
The rest of the post is divided up into the steps you'll need to get things up and running
- Setup Apache (including VirtualHost)
- Setup Php-FPM
- Test the setup