X10 is a costy professional switching system, with quite limited capabilities (no automatic cat feeders or a cat cam for example).
So you might consider playing with Arduino
www.arduino.cc
This is a small stand-alone "computer" that can be programmed with ease over USB. The nice thing is that Arduino does not use much power compared to running a full PC. It is so small, you can hide it wherever you like.
From the basic Arduino, you can add several shields to switch appliances.
There is a relay shield for 110/220V switching
You can make Power-Mosfet shields for high frequency 110/220V switching
You can add an XBee shield for wireless control of other XBee switches.
There is a big bunch of input shields to read RFID, measure temperature, measure light, sample sound etc.
Pricing is great. Arduino costs around 20$, most shields do a similar price, and if you can solder you can cut on costs even further.
A good source for arduino projects is:
www.makezine.com
They have a nice store too:
http://www.makershed.com/SearchResults.asp?Cat=43
Good books on the subject are "Making things talk" and "Getting started with Arduino"
If you buy the Arduino starter kit, you have a great set of components to start with automation, and the nice book "Making things talk" is included as well.
Need to compare and contrast options, if possible. For example, some require serial lines running to appliances and some are wireless while some use the power lines in your house to communicate with the controlling device. It would be hard to compare apples to apples, but some of these implementation details are deal breakers for me, like the serial cable running through my house. I would never go for that one. – Kurt W. Leucht – 2009-07-30T21:02:47.310
Oh yah, I completly agree with you. These are just some of the options out there. I have not heard of a tried and true approach to this question yet, but there are options out there. – Troggy – 2009-07-30T21:19:54.570