Magento get Category and Sub category details

When you are customize the magento site you may be want to get current category,root category and sub category details like category ID,name,…etc.Here is a simple example.

// Load libraries
$layer 			= Mage::getSingleton('catalog/layer');
$_category 		= $layer->getCurrentCategory();
// Get Current category ID
$currentCategoryId	= $_category->getId();
//Get current category all details
$current_category 	= Mage::registry('current_category');
// Get Parent category ID of the current category  like root category
$parent_id 		= $current_category->parent_id;

If you want to load known category details ,for a example want to load category id=10, details.That is like this.

	$_category = Mage::getModel('catalog/category')->load(10);  // category ID=10
	echo $_category->getUrl();  // get category URL
	echo $_category->getUrlKey();   // get category URL Key
	echo $_category->getName();  // get category Name