I only have two global vars in my project, userid and config. userid is supplied by the user, config is stored using wddx.
Here's how I do config:
// Load the data
touch("$configDir/config.xml");
$config = wddx_deserialize(implode("", file("$configDir/config.xml")));
// Save the data
unlink("$configDir/config.xml");
error_log(wddx_serialize_value($config, "MyApp Configuration"), 3, "$configDir/config.xml");
So config is an associative array stored as xml using the wddx dtd and it is stored on the server in a plain text file. I think this is what you are looking for.