Zend Framework style autoloader

spl_autoload_register('autoloadByUnderscore');
 
 
function autoloadByUnderscore($class) {
	$pwd = dirname(__FILE__);
	$filename = str_replace('_','/',$class) . '.php';
	$path = "$pwd/../lib/$filename";
	if (is_file($path)) {
		require_once $path;
	}
}
 
// or rediculously simple:
function autoloadByUnderscore($c) {
	require_once(dirname(__FILE__) . '/../lib/' . str_replace("_", '/', $c) . '.php');
}