He isn't messing with time in the game - he built a separate iPad app that allows the user to calibrate the time manually to that of the minecraft server.
Even easier, you could just write a minecraft server plugin that puts its current server time somewhere for the app to read from. It could be anywhere, really - the plugin could run a webserver, the plugin could put it in a txt file visible online somewhere, etc. Now all the iOS app has to do is cat the time and sync automatically.
