Pierric Gimmig has found an inexpensive remote-controlled toy car and modified it in order to allow control via Arduino and a PC. The interface is simple enough - by using optocouplers each button from the remote transmitter can be activated by the Arduino digital output pins. The car then supports a larger frame with the electronics and notebook computer, which will then receive commands from the Internet and relay them to the car. For example:
As you can see from the RixRover project, some external circuitry was required and this can be housed nicely on our Freetronics Terminal Shield for Arduino. The Terminal Shield breaks out all the Arduino headers to handy screw terminals, making it really easy to connect external wires to your motors without using a soldering iron. Ideal for quick experiments or for robust connections!