Note to Apple: For this to truly become the future, you need to open up hardware accessibility to third parties! (Although logic dictates you may already be working on this.)
iPhone + home automation
Apps: iPhone Home Controller 2.0, Smarthome
Imagine being able to read the contents of your fridge by glancing at a list stored on your iPhone; dimming the kitchen lights with a gesture on the touch screen; and finally being able to determine beyond all doubt that you did, in fact, turn the iron off.
As we march into the future, there is an emerging marketplace for mainstream hardware that bridges the gap between the iPhone and household appliances. While direct-connectivity options built into appliances are the next logical step, there are currently third-party options that enable home automation for existing homes.
Be warned, however; home automation is getting better, but it's still all rather geeky and niche-y, complete with dedicated online forums run mostly by ?ber nerds who are to regular nerds what nerds are to normal people. If you're still curious after that caveat, there are a few sites that offer complete solutions, including Smarthome.com and the iPhone Home Controller 2.0.
For examples of home automation via the iPhone, the Smarthome site even offers a Web video that demonstrates dimming lights, turning on and off sprinklers and adjusting temperature. It also shows the ability to monitor all of the actions remotely using an IP-based Web camera.
If you still want more, check out this list of home automation software , compiled specifically for the iPhone, including many more options than I'm able to cover here.
iPhone + video
Apps: Baby Monitor, SecuritySpy, Cam Viewer, Air Cam Live Video
Speaking of convenience around the home, the iPhone's ability to play video streamed from the Web makes it extremely useful in terms of home surveillance, from security aspects to tasks as mundane as watching a baby.