I'm looking to create a fully functional installer for a slightly complicated web application using PHP. Basically, you go to URL/setup.php and you are asked a series of questions, and during the process a database is set up and a config file is populated according to the answers given. A good example of this is how Wordpress handles its install procedure, as well as any number of PHP applications.

My question to you, oh great internet, is this: This technique is so prevalent that surely not everyone is re-inventing the wheel, is there a place I can go to find a basic walkthrough (not code, just a description) of the technique. Either that or a good book which outlines if not this specific technique, then the fundamentals relevant to this?

I can bang out something ugly and probably make it work myself, but if there's a best known method I'd like to find it.

Far more important than having a working function is to have a description of what's going on from step to step. I'd like to have the installer, but I really want to learn how it's done.

Thanks, Mike