I got a old RC car at a thrift shop ??? and it has a RX2 chip in it. I looked at this thread
http://forum.arduino.cc/index.php?topic=86883.0
and thought it was cool. So I did it myself! It works great, but I need a 6V battery pack. So I used a LM2576 regulator to get 5V and changed it to get 6V. I hooked the chip up, and it drives!
After I drove it around for a bit, the batteries started to sizzle. Turns out I had put one of the 8 AA batteries in backward! So now I need a new battery. Luckily, nothing else burned 
I will post pictures as soon as possible.
Ok! an update! I used monsieurDavid's code GitHub - monsieurDavid/rx2-hacks: Fun with RX2 driven remote controlled toys. and it is even simpler! I am going to try to control it through a RF link.
But the RF link doesn't work! Oh no! What do I do now?
So I used a RC system, and it works! But I had to offload the actual sending to the chip to a ATTINY4313, because the code behaves badly with interrupts or pulseIn().