If you think the smartphone market is interesting now, just wait until the fourth quarter. Smartphone giants Research In Motion (BlackBerry), Nokia (MeeGo) and Microsoft (Windows Phone) each plan to introduce by year-end completely refreshed--or in some cases completely new--smartphone platforms. The actions highlight the dramatic and continued upheavals in the smartphone playground, as well as the market's massive opportunity. But is there enough room in the smartphone business for all this busy-ness? Special report