Its very easy to control a bot through a parallel port. i have designed mine and its working fine. but i dont have a camera thought. i controlled it thru C program.
All you have to do is to send the correct bits to the parallel port and for that you must know the parallel port address (usually 0x378). once you get the bits, just send them to a motor driver and that will turn the motors. make sure you isolate the motor driver and the port with an opto isolator. just google for more info.
If you want to use serial port then you need a microcontroller. it is simple, but i wont recommend it for a beginner.