How to get all Store Ids in Magento

<?php
$allStores = Mage::app()->getStores();
foreach ($allStores as $_eachStoreId => $val) 
{
$_storeCode = Mage::app()->getStore($_eachStoreId)->getCode();
$_storeName = Mage::app()->getStore($_eachStoreId)->getName();
$_storeId = Mage::app()->getStore($_eachStoreId)->getId();
echo $_storeId;
echo $_storeCode;
echo $_storeName;
}
?>