How to get Magento system configuration value?
It's easy:
Mage::getStoreConfig($path, $storeCode) // $storeCode is not required
for example you need to get value set for store phone number from system config:
Mage::getStoreConfig('general/store_information/phone');
Also, you can get configuration value as true or false like this:
Mage::getStoreConfigFlag('general/store_information/phone'); // return true
Mage::getStoreConfigFlag('general/yes_no/choice'); // true or false based on selection