This is an app for java mobile phones with in-built GPS. It makes it easier to submit new postcodes to the Free The Postcode! service.
It should just be a case of clicking here.
If that doesn't work, you could try to install the jar file directly.
So far it's only been tested on my Nokia N95 8GB. I'd be interested to hear of any other phones it does or doesn't work on. Email me at adrian-blog@mcqn.net.