If your home or business uses the Wiser home controller technology from Schneider Electric, there's now an iPhone app you can use do mess around with things from a remote location.
Wiser works with the C-Bus home automation technology that is embedded into certain lighting and heating, air-conditioning and ventilation (HVAC) systems, or even home irrigation systems. The free download works with any aspect of the Wiser system: you can turn off lights remotely, adjust the thermostat settings, and so on. Of course, this all moot if you don't have the Wiser system in the first place.