First, let’s talk about how to get category by category id in Magento.
It’s easy to get category by id, just change the number in load() method.
$category=Mage::getModel('catalog/category')->load(23);
Then this is the dsecription:
echo $category->getDescription();
You can change the description in Catelog->Category in the backend, and you can easily get other attributes just change the getDescription() method.