Hi, and though this might seem like self propaganda, I really think people might be interested in this:

A friend of mine and I have come up with a PHP script that we call DBX, and it is a small scale Database engine.

What's cool about it is that it's a small(<20k) DBMS, and it takes in basic SQL queries and stores the data as XML...

Since it's SQL, you can easily port small mysql php scripts to dbx and run them rightaway... it's also perfect for small sites that have php, but dont have MySQL.

We've put in quite some work into this, and would like people to use it - it's freely available for download at dbx.idya.net

(note the download form of the site - it runs on DBX!!!!)