in the manage category page I have cms block which I want to update it programatically I guess that the attribute id to set for this is landing_page

unfortunatley I don't know the function to get the landing page or get the cms block value

for example in this case Category Listing how can I get that by collection?

$category = Mage::getModel('catalog/category')->load(17048);

also

echo $cat->getAttributeText('landing_page');

it doesn't show me anything