Microsoft dropped a semi-bomb by stating that its next-generation mobile operating system -- Windows Mobile 6 -- will be coming to T-Mobile USA shelves in the second quarter of 2007, according to Microsoft. This just-released information -- which had previously been embargoed by the software giant -- was given after an extensive pre-briefing on its capabilities to wireless industry analysts and press this week. Based on information from Microsoft officials, the latest version of Windows Mobile will be given first to T-Mobile here in the U.S. before any other wireless carriers get their official mitts on it. The question then becomes: Will T-Mobile USA immediately make the OS upgrade available to owners of current-generation WM5 devices? After all, there are "ten thousand" changes in WM6 from WM5 according to Microsoft. We hear some massive testing by T-Mobile USA in the near future.