Thermoduino is a thermostat based on an arduino microcontroller board with ethernet shield connected to your heatingsystem. This version is no longer under development. A new pro version will be available in google play soon.
After setting your IP and port this android app can be used to control you home temperature.
The Thermoduino is built using the following components:
Ethernet Shield W5100
DFRobot LCD Keypad Shield
2x DHT22 Humidity and Temperature sensor
2x 2 channel 5v relay
The sketch for the arduino can be downloaded here http://db.tt/UJ1SxZXf . A description how to connect the two relay's to your heating system can be found in the sketch. Only arduino mega is compatible due to sketch size.