Stanley:

You should consider the use of low cost ready made stuff for the power controls. There is equipment referred to as "X-10" Controls which is made specifically for doing what you are proposing. Many X-10 type products are displayed and sold through the web site at: http://www.smarthome.com/

There are also ready made transmitter devices which you can connect to via RS-232 from your microcontroller which can then send the control signals over the power line. Here is a link for one of these devices: http://www.smarthome.com/1140.html

Michael Karas