gistfile1.php

<?php

function find_person($value, $search_term){
	foreach($value as $category){
	    if (isset($category['children'])) {
		    return find_person($category['children'], $search_term);
	    } else {
		if ($category['name'] == $search_term) return $category['person_id'];
	    }
	}
}

$AoH = array(
	'name' => 'beavis',
	'person_id' => 'bvs',
	'children' => array( 
		array ('name' => 'dave', 'person_id' => 'dve',
			'children' => array(
				array(
				'name' => 'cornelius',
				'person_id' => 'crn'
				)
			)
		),
		array ('name' => 'cornholio', 'person_id' => 'bth')
	),
);

$the_person_id_i_want = find_person($AoH['children'], 'cornholio');
var_dump($the_person_id_i_want);
?>

'beavis', 'person_id' => 'bvs', 'children' => array( array ('name' => 'cornholio', 'person_id' => 'bth'), array ('name' => 'dave', 'person_id' => 'dve') ) ); $the_person_id_i_want = find_person($AoH, 'cornholio'); var_dump($the_person_id_i_want); ?>