IPhone development initial video to explain concept:
The final game produced:
"It starts with a wiki; the company keeps a collaborative site of all the ideas they have for upcoming games, and if the decision is made to go ahead with an idea, that wiki page branches out into the planning documents behind the eventual app. Concepts are drafted in sketches, conversations, and outlines, and eventually they feel like they have the idea "fully developed," at which point the game goes into a proposal pool, and then is eventually picked for production."
For further information check out Mike Schramm article here