My EPFL co-worker Fabien wrote a postmortem report (.pdf) about our CatchBob! project in which he describes the whole development process. He presents how we designed CatchBob on two platforms (namely iPAQ and TabletPC) and how he implemented it. The report goes throught the whole thing, dealing with the game architecture, the user interface, the positioning feature as well as the communication tool (that allows to annotate the map).