Remote controlled things usually require transmitter and receiver. Building both of them doesn’t always sound attractive. By using bluetooth module it can be simpler. Take a look at Mike’s Bluetooth msp430 tank.
Its control unit is based on MSP430 Launchpad paired with wireless Bluetooth module. Two motors move threads. Of course there is a motor booster needed. When all set all you need is to send control commands via bluetooth channel. All you need here is to install small application in to your Android phone and you can start crawling around.