//To register to PHP's GLOBALS array...
$GLOBALS['myVar'] = 'registered";
echo $GLOBALS['myVar'];
//to register a constant...
define('myVar',"registered");
echo myVar;
the diference is that the $GLOBALS are dynamic and may be set and unset at a whim,
where constants are static once set.
They can be handy when dealing with values you never want reset during a scripts execution and want available on the Global Scope.
Regular old $GLOBALS are the most versatile way to go.
