Free Shipping Based on Postal Code Zone?

[DrByte]

I haven't studied your PHP code, but I did spot this problem:

$free_ship_postcodes = array('4328, 4031, 4329, 4327, 4032, 4005');

Each value in that array should be in quotes separately, like this:

$free_ship_postcodes = array('4328', '4031', '4329', '4327', '4032', '4005');