i'm thinking way way in advance here.... our prototype for our design project next year needs to be able to be powered on and off, and have speed adjustments carried out remotely (by remote control

). [project is top secret, but anyway...]
so, can anyone give me any pointers to sites and things that would help in designing a remote control system? due to the nature of the product, IR would not be suitable, would need to be a RF system with as small an aerial as possible. i'm thinking of getting a small RC car and cannibalising it for parts to start with, but if anyone could give me any pointers i would be grateful.
basically, a speed of between 0 and 5mph needs to be adjusted remotely... i'm not exactly the best in the world at electronics (despite A* gcse electronics) so pointers would be helpful