Maurício developed a Arduino based project for controlling devices in your home over the web. The site is in Portuguese but the video has English captions. The project uses the ethernet shield to allow you to interface with the Arduino over the web, which in return controls relays.
How to turn on lights, and various home appliances is demonstrated in the video, as well as how to get rid of useless garage door remotes. All of this is done via a smartphone with internet access. He has provided the source code for the firmware.