Magento How to get product stock quantity & other stock information?

1. Load product by product ID
$id = 52;
$_product = Mage::getModel('catalog/product')->load($id);

2. Load product by SKU
$sku = "microsoftnatural";
$_product = Mage::getModel('catalog/product')->loadByAttribute('sku', $sku);

Now, get stock information for the loaded product.
$stock = Mage::getModel('cataloginventory/stock_item')->loadByProduct($_product);

You can check stock data in this way:-
echo "<pre>"; print_r($stock->getData()); echo "</pre>";

Or, you can print individually like this:-
echo $stock->getQty();
echo $stock->getMinQty();
echo $stock->getMinSaleQty();