I personally would say scrap the native app and make a Web App and Dev Kit for people.
Mobile Safari can read your cords off the GPS and a WebService like geocaching.com could host the decision engine, videos, animations, ect.
Here is how to use it already:
http://mapscripting.com/how-to-use-geoloca...n-mobile-safari
Lets get this rolling.
This would work for all phones too that could support the web and if it's a standard W3C than thats a bonus.