Here is an electric water heater controller that lets you control your heater from anywhere using smartphone and tablets. It uses a Belkin WeMo light switch and has manual / auto modes. The app for iOS and Android lets you program the heater just how you want.
The Red Coral water heater controller can be controlled over WiFi, 3G/4G connections. It is IFTTT compatible. Costs under $200 at this time.