Rob Arnold have built a simple robot platform that can be controlled via RF channel. To make things simple he used a RWS and TWS 434 RX/TX pair from Raynolds Electronics. Working with these modules is quite simple – you can simply connect them to MCU serial (USART) port. This job can be done with simplest PIC16F84 microcontroller.
Actual project consists of two parts – receiver (the robot) and transmitter (joystick). Robot itself is driven by two servo motors which speed is changed with potentiometer based joystick on receiver part. Project is easy to build but it can be a great fun to play with especially for kids.