There is definitely a market for this. International payment gateways like CyberSource (www.cybersource.com) are extending their services to include address va

There is definitely a market for this. International payment gateways like CyberSource (www.cybersource.com) are extending their services to include address validation (and correction), fraud detection, etc. It would be very hard for a startup to compete in this space though - perhaps a better opportunity for a partnership between a payment gateway and a major distributer.