Anyone look into doing this? From what I understand, ZWave is the best:
ZWave Commander - iPhone/iPad/iPod/Android ZWave Controller
With ZWave, you get a standalone hardware router, and they have some extremely cool shit. Like setting your thermostat, or zwave deadbolts - basically you could unlock your house with your phone.
Initially I'm looking to just do lights, and to run a multi-room media server, but this seems a lot cooler than the X10 stuff, which is generally considered shit in most circles. (Their API is easy to work with, however)
There's also this:
Which requires a dedicated server, but you can hit it via the web, and do things like adjust your thermostat remotely.