Building interfaces to common household appliances (i.e. home automation)

[Descartes]

I know that some appliances (although I don't think I've ever seen any) have PLC's (programmable logic controllers) in them, but I'm curious as to how one might go about building my own. I've written a small system in C that maintains it's own internal filesystem (i.e. no need for hard drive), and exposes both HTTP (to administer the system) and SMTP (for notifications) interfaces. I borrowed part of the concept from an article in Dr. Dobb's, but I built it for a Win32 environment. What would I need to an interface to something even as simple as a television, lamp, etc.? I'd like to at the simplest level be able to control power operations (simply turn it on/off). I'll be building XML interfaces into the HTTP interface of the system, and rendering presentations for a web browser and my cell phone, so I can administer my appliances anywhere I want. I have no real purpose behind this, I just want something fun to do. I do know that some thermostats implement a PLC, but I'm quite sure mine doesn't. Getting remote read-outs of the current temperature in my home, and the ability to adjust it would have been cool too, but I doubt that'll happen.

Sorry for the loquacious post, but anyone have any ideas?

 

[MadRat]

I'd gear for the parrallel or serial port as a potential interface.

 

[Markee]

Some cool PIC microcontroller based complete web servers out there.
A web search should spit them out. However, looks like Bluetooth is what you really want?

 

[LordOfAll]

Cant answer any specifics but I think this site here will help you out a lot.

Interfacing

 

[BurntKooshie]

My friend used the parallel port to control a remote-controlled car. I can ask him where he got his information if you'd like.