as far as I'm concerned, nothing is more intuitive than simple textfiles with lines like
#this is a comemnt line
database = 'my database name'
etc.
Off course, that is up to you, but that is what I would go for.
give them their own textfile, let them replace the values by what you allow them or comment those they don't need out. Very easy.
Take a look at ConfigReader class (dunno where I ever found it, mail me if you can't trace it via Google).