simple pagetree dca

pagetree.dca

$GLOBALS['TL_DCA']['tl_page']['fields']['mymodule'] = array ( 
    'label' => & $GLOBALS['TL_LANG']['tl_page']['mymodule'], 
    'exclude' => true, 
    'inputType' => 'pageTree', 
    'eval' => array ( 
        'fieldType' => 'radio', 
    ) 
);