On the FWebDe blog there's a recent post from Eric Bannatyne about using SQLite in your next project.
SQLite is one of those awesome pieces of software known for its "liteness". It is, as you can guess from the name, a database designed to have as small a footprint as possible. SQLite is a very popular database, in fact, it is believed to be the most widely deployed SQL database engine in the world.
He gives some reasons why to choose this database tool and introduces you to some of the basics - creating a database, connecting to it from PHP and running a query. He ties this all together in a complete example of connecting to the database and inserting post information into a table.