Home Automation Lighting is exactly what i am gonna do. In my project we can control lights using computer via internet(I think with arduino web server). Also control with my android phone. I want to make an android application for this.
But i am not sure which arduiono is fit to my project. I think 'Arduino Mega ADK' and 'Arduino Ethernet Shield w/o PoE R3' is enough for me. I dont know this things is compatible for each other. I am new with arduino. I dont wanna buy wrong things. Please help me to choose and give me hint for good starting.
Everything you want to do is possible with Arduino. In fact, my home automation system functiodomo is done with it.
About the PCB that you need you have to consider that you need for each control PCB (Arduino) , 1 transformer, one communication board and one power board to work over the 220VAC.
You can see a scheme at my thread:http://arduino.cc/forum/index.php/topic,92963.30.html
(the post of castillo14 are mine; it is in spanish, but I think that the schemes are clear)
You can find more information about it at my web http://www.functiodomo.com
where you have an english section.
Anyway, after I built a prototipe, I decided to design my own PCBs (100% compatible with Arduino platform) to achieve a easier installation. You can see them at this english tread: http://arduino.cc/forum/index.php/topic,116788.0.html