Actually that last post is incorrect ....
You can turn on register globals by editing or creating an .htaccess file in your doc root.
Setting up a .htaccess file
If you want to activate global variables, you will need to create or edit the .htaccess file in your site's main directory (or the main directory of your site that contains PHP scripts). Your .htaccess file should contain the following line:
php_flag register_globals on