GET ORDER DETAILS FROM ORDER ID IN MAGENTO :

<script>
$orderIncrementId = 10001222;
$orderId = Mage::getModel('sales/order')
->loadByIncrementId($orderIncrementId)
->getEntityId();
</script>
You can get order details by order increment ID as follow:

<script>
$order = Mage::getModel('sales/order')->loadByIncrementId($orderIncrementId);
</script>
If you know the real order ID you can get order details by using following code:

<script>
$order = Mage::getModel("sales/order")->load($orderId);
</script>

To get order total value:
<script>
$orderTotalValue = number_format ($order->getGrandTotal(), 2, '.' , $thousands_sep = '');
</script>

To get order items collection:
<script>
$orderItems = $order->getItemsCollection();
foreach ($orderItems as $item){

$product_id = $item->product_id;
$product_sku = $item->sku;
$product_price = $item->getPrice();
$product_name = $item->getName();
$_product = Mage::getModel('catalog/product')->load($product_id);
$cats = $_product->getCategoryIds();
$category_id = $cats; // just get the first id
$category = Mage::getModel('catalog/category')->load($category_id);
$category_name = $category->getName();
}
</script>
To get shipping method from order:
<script>
$shipping_method = $order->getShippingMethod();
</script>
To get payment method code from order you can use following code:
<script>
$payment_method_code = $order->getPayment()->getMethodInstance()->getCode();
</script>
I hope this tutorial will help you to get order details from order ID in Magento.