$params = new JRegistry( array('key' => 'val') );
$params->get('key');
// -------------------------------------- XML Parameters
// Parameters
$params = new JForm('params');
$params->loadFile( JPATH_ADMINISTRATOR.DS.'path-to-xml' );
$params->bind( (array)$row['params'] );
$fields = $params->getFieldset('params');
foreach( $fields AS $field => $obj ){
echo $params->getLabel( $field, null );
echo $params->getInput( $field, null, null );
}