magento 1.9: How to load customers by mobile number

You can search by below code, you can set your attribute value instead of telephone:

$telephone = '32423423';

$result = Mage::getModel('customer/customer')
    ->getCollection()
    ->addAttributeToSelect('*')
    ->addAttributeToFilter('telephone', $telephone) //replace your attribute of mobile
    ->load();

if (is_object($result)) {
    //set your code...
}

At magento telephone is Customer address attribute.

If you want to get Customer details from telephone then you need to check Customer Id from Mage::getModel('customer/address') model.

    $CustomAddress=Mage::getModel('customer/address')->getCollection()->addAttributeToFilter('telephone',$YourValue)->getFirstItem();

    $customerId= $CustomAddress->getCustomerId($CustomAddress);

Then using Customer id,You can get Custome data by load Customer model

$customer = Mage::getModel(‘customer/customer’)->load($customerId);