For those people who do not know what that is... : the Cybot was a small robot which could be build from prefabricated parts, sold (I think) on a monthly basis with a magazine.
The final robot featured a own programming environment where simple behaviors like line following, light seeking or object avoidance could be programmed. In the final parts of the series, the robot could seek an IR-emitting ball, catch it and transport it to a goal. It was also able to react to spoken commands via a headset.
Now, there are still some webpages around dealing with the circuits of this little robot; some people reverse-engineered as much as possible, even were able to figure out the PICs used in the design....
Here are are some links to get you started:
Just a few comments: the Cybot featured two quite strong motors; if you have the motor-driver board as well, it is rather easy to connect that to an Arduino. This should make a simple but fast robot base.
Depending which parts you actually have, you could also use the line-sensor of the robot for line-following and the LDRs for light seeking experiments. The Cybot also featured two ultrasound sensors (pairs of transmitter and receiver) - with enough electronic skills, one could reuse these for an home-brew ultrasound distance ranger.
Communication was done via IR, but as far as I know, an own communication protocol is used. Besides communication, IR was also used for beacon location (namely locating the IR-"soccer ball" and the "soccer goal", which featured also an IR-transmitter).
The different electronic parts and PCBs, for example the ultrasound board, are quite ingenious; after all, the designers tried to achieve a maximal effect with a minimum of effort (and costs). The designers used several PICs and discrete circuits in their robot. I think the different modules used something similar to an I2C-bus for communication, but I am not sure.
As remarked, the motor-driver board is a simple H-bridge type design and can be easily incorporated into an own design. The other stuff might be harder to use directly; people soon started reverse-engineering the Cybot at the time it was published. However, not many people followed the publication all the way through - so there is little information available on parts which appeared later in the series, like the remote control (including a LCD-display) and the speech recognition circuit.