Create a file with the following code in it.

<?php
phpinfo ();
?>

Save it on your server and access it through a browser.
On my server it says..

Configuration
PHP Core

Directive Local Value Master Value
register_globals On On

Master value is the value set in php.ini.
Local value is a setting set with something else, a .htaccess file for example. You can create an .htaccess file with one of the following line in it...

php_flag register_globals on
php_value register_globals 1

Now next time you can access variable just by printing it to the browser..

print $username;