The idea is to build a wireless remote control, communicating using bluetooth. This is going to be a quick, very rough build, and it assumes there's an already established server-entity and communication protocol. (You can write a quick one in your language of choice - it just has to be able to receive and send commands through a bluetooth radio).

Gather the parts and start prototyping the circuit on the breadboard. Set up the power and ground rails first, then build on up. BT Radio I/O goes to the corresponding I/O of the Arduino (invert the paths), the regular LED should go from a digital pin to ground, and button should be wired properly (either using pull-up or pull-down techniques). The IR Led should be attached to digital pin 3 and the receiver, pin 5.

Load up Ken Shiriff's IR Library (http://www.righto.com/2009/08/multi-protocol-infrared-remote-library.html) on your Arduino sketch and push the 'relay' example to the Arduino to test if it works. Make sure to change the necessary pin layouts in the sketch to match your own circuit layout.