Well the common way is to buy an RC set (transmitter, receiver and servos), modify two servos for continuous rotation to drive the wheels, plug the servos into the receiver and go. There just isn't any electronics or programming required.
Look for info on Battle Bots for RC control.
On the reverse side there are a number of threads here about using various radio links to send commands to a uController in the robot. Common radios are Bluetooth, XBees, WiFi and a few others. These normally don't require much knowledge of radio circuits but can take much programming. Since there are so many inexpensive radio modules available and since building radio receivers are rather difficult it isn't really worth the effort to build your own.
