Magento: Regions list related by country

Function to get Regions list by Country:

 public function getRegionCollection()
    {
        if (!$this->_regionCollection) {
            $this->_regionCollection = Mage::getModel('directory/region')
                ->getResourceCollection()
                ->addCountryFilter($this->getAddress()->getCountryId())
                ->load();
        }
        return $this->_regionCollection;
    }

 

Adding More States and regions to the countries:
http://www.sycha.com/magento-add-custom-state-province-region-country