The RC car projects did not require a huge amount of equipment to create, the most difficult part of this project was creating the program to control the car but I have provided the code I used here so that shouldn't be an issue for you.
So in total you will need:
The Velleman k8055 usb interface board is perfect for interfacing your computer with the outside world if your not a computer genius.
It has the ability to send out signals and receive signals from your device meaning you can connect anything you can think of to the computer and have it control the device for you.
The board comes with software for testing your inventions and lots of code to help you create your own programs easily.
I have been told of another board called an Arduino but I have not used it myself. I'm sure you would be able to modify an code on this site to work with your own board without too much difficulty.
Obviously you will need an RC car to do this project, it doesn't need to be new one any old car will do. The only important thing to note is that the controller has simple joysticks i.e. no potentiometers. You will know that the car has potentiometers in the controller if when you push your joystick forward the car slowly accelerates. The kind of car you need for this project come on full power when the button is joystick is pushed forward.
The only modification which is required is a change to the controller of the car but this is a simple task which you will find here.
The car the code is written for was a standard RC car with normal forward, backward, left and right i.e. it did not move like a tank. This could be easily accomplished by changing the code or just getting used to the controls.
I used Visual Basic 2008 Express Edition to create the programs you see on the site. It is free to download and all you need to do is drag and drop all the components onto the screen and then add the code from the project to your program and away you go. If you have any difficulty getting the programs to work contact me or post your question in the forum so that everyone can benefit.
If you'd rather just get the program you can download it from the freebies section.
You'll probably have a good supply of these things scavenged from different devices so I don't think there is need for much detail here. You wont need a lot for this project as you'll only be adding a few wires to the controller.