Info on the Bluetooth G-Shock GB6900AA-1 just posted by Casio apparently? (here also).
iPhone Mobile Link Features
Notification of incoming calls and e-mails via the watch
Phone Finder function to enable iPhone alarm function from the watch
Warning vibration when the watch loses its connection to the iPhone
Time adjustment by synchronizing with time data received from the iPhone
Built-in tilt sensor to detect movement in the watch, while it is in power-saving mode, to automatically reconnect to the iPhone