Marc Merlin controls his house lights and air conditioning with his computer, and he wanted to tell us about it. He wanted to teach his cat some manners. The cat knows it isn't allowed on the kitchen coutner, but also knows he won't get caught at night. So one way is to have a blender on your kitchen counter triggered by a motion sensor. But a motion sensor isn't targetted enough, it could trip at the wrong time. So another way is to use some motion detection from a web camera.
Misterhouse was written about 10 years ago to allow for complex home automatino. It's based on perl. It supports almost all open protocols. Has a helpful mailing list, email@example.com. It can turn lights on based on a switch, and a motion sensor, with correct logic (disabling motion sensor time outs if you used the switch).
It supports X10, Insteon, Z-Wave, UPB, 1-wire. x10 has a few issues. X10RF is a radio frequency antenna way. But X10RF still has some problems. There is also X10sec, which I didn't listen to why it's different.
Looks like you use misterhouse by writing perl modules. He showed an example with X10 stuff. He then described Insteon, which is better than just X10. But there is no support in Australia or New Zealand.
1-wire is a bus topology network. You can run your wire runs for about 1000ft. The 1-wire interface is pretty cheap. There is also Oregon Scientific WMR200, which is cheaper wireless weather solution. Then he talked about XPL, a network protocol to broadcast sensor data. I tuned out, even though the talk was pretty interesting. Later on I noticed he was saying that he was able to graph the powe rusage of individual appliances, and correlate various temperatures to when things were switched on, so it looked pretty powerful.