#1 Investigate free location data sources /web services

[neale]

Investigate adding location support using open source geolocation, such as:

UK:
www.npemap.org.uk
www.brainstorm.co.uk
www.jibble.org
www.freethepostcode.org

Global:
see http://www.geonames.org/postal-codes-sources.html

Geonames does have downloadable data. Coverage is so far good, but not fantastic.

A caching use of their web service would probably be sufficient, given that it limits at 50,000 queries per day.