get products from category id
<?php
$products = Mage::getModel('catalog/category')->load(576)
->getProductCollection()
->addAttributeToSelect('*')
->addAttributeToFilter('status', 1)
->addAttributeToFilter('visibility', 4)
->addAttributeToFilter('special_price', array('neq' => ""))
->setOrder('price', 'ASC')
->getData();
?>