Is there a source (free or paid) for polygons of border coordinates for spanish postcodes? Google show this borders in google maps, but doesn't provide them.
For paid for postal codes for Spain (mapa código postal España)
Spain and Andorra (mapa código postal España) GfK GeoMarketing offers up-to-date postcode / postal (mapa código postal), administrative (Municipios, Comunidades Autonomas) and topographic digital maps of Spain for use in geographic information systems (GIS) and mapping software.
digital postcode maps for GIS
2-digit postcode areas 5-digit postcode areas
Declaimer: Have in the past used gfk-geomarketing data sets they are good quality but am not associated in anyway with the company.
I only did a quick search but try here:
The WMS at http://www.cartociudad.es/wms/CARTOCIUDAD/CARTOCIUDAD?Request=GetCapabilities provides a layer called "CodigoPostal", which seems to contain postcodes. As far as i can see the layer is queryable.
I found this WMS by searching with google for "código postal España inurl:wms".
I don't know enough spanish to decide whether this service is free/legal/illegal to use.
The capabilities state
<Fees>no conditions apply</Fees> <AccessConstraints>OtherConstraints. Se permite cualquier uso si se menciona la autoría del IGN del siguiente modo: «© Instituto Geográfico Nacional de España»</AccessConstraints>
Geo-referenced maps of the Spanish provinces with 5-digits postalcode areas. Shapefiles and KML. The Shapefile format are associated with their database and ready to incorporate your own data and overlay on SIG applications (Geographic Information Systems). KML is a file format used to display geographic data in an Earth browser such as Google Earth, Google Maps, and Google Maps for mobile.