They can be used if for a simple purpose.
The functions used can also be used for things such as writing directly to a file, making changes to the coding of a file via code or even creating whole files on the fly.
The best resource for most things is the php manual itself. I know it isn't a tutorial but even I learned flat file database and how to do it via the manual! Do a search for 'fopen' and the other functions are linked in the page. Most fo them begin with 'f' such as 'fopen' and 'fclose'.
If you want to have a database for anything much more than 'stupidly simple' then yeah...do as devinemike said himself - go point a browser towards MySQL! They don't have to be complicated as the tutorials like to make them sound! (most of em are written by showoffs anyway!)
