有没有办法在magento中检测地址是否已经存在

Is there any way in magento to detect if an address already exists.

The customer can decide - in the OnePageCheckout - if he want to use an existing address or enter a new one. If it is an existing one i don't want to / need to validate it.

So is there any way to find out if it's a new address or not?

You can get full list of loged customer adresses, by using this code:

$customer = Mage::getSingleton('customer/session')->getCustomer();
foreach ($customer->getAddresses() as $address) {
    Zend_Debug::dump($address->debug());
}