Is there a postcode for deliveries checker module for drupal 7?
There's no single module for this, but you can use a suite of modules.  For example, you can take addresses stored in the Address Field module and then use Geocoder to geocode them and save the results in a Geofield.  You can then use Rules to check the distance.

That said, there is no simple way to do this.  In fact, there's an entire book about Mapping with Drupal.