I am looking to build a simple GPS peering application to display a map of coloured pins to show whereabouts of a team. A device sends GPS pings as background thread to a simple web-service that keeps track of all the data. Each device receives the tracking data as required to display the location of other registered devices on a common map. I want the application to work on iPhone, BlackBerry, Android. I have attached a simple PPT, to give context. We can discuss specifics as required.

The developer must have Android, iPhone and BB experience and be able to provide web-services or robust equivalent for the server-side to work with all three versions. You must be able to provide these requirements. There is no point in bidding for an application that doesn't communicate with a server! The bid must be below USD 500 per device.