Update 12/6/13:
Unfortunately I stopped work on this project when we moved last year and this was left with a relative. I still have not gotten it moved to our new house, and I am working on another project which takes all the time and money away from this one. I'm not sure when I'll continue working on this, hopefully next year.
FYI:
The steering system in this instructable was a first test, and it didn't work very well. I would suggest a stronger, bottom mounted servo or linear actuator.
Here is an instructable that was just published and goes into detail about using an xbox controller and a linear actuator for steering.

Welcome to my first Instructable!
This is my first time using RC receivers and transmitters, so please comment if I get anything wrong or to make this instructable better.
Please vote for me in the Remote Control, Spy, or Robot chalenges!
I have had a Power Wheels ride-on Jeep since I was a little kid, but I'm getting a little too big to ride on it. So, I decided to make it into a robot.
This robot will be controlled by a FlySky FS-GT3B, and eventually will have a netbook on it to Skype another computer. There are a lot of instructions and posts all over the web on how to make your Power Wheels rc, but non of them are complete step-by-steps. I am trying to do this here.

Update 6/15/12:
-This is part 1: Steering. Part 2 will be getting it to go forward and backward, which I am working on soon. I am currently waiting for a Sabertooth controller to come in the mail, and this instructable prepares the Jeep to get wired to it.
-I did a black paint job with a special spray paint that bonds to plastic without sanding called Krylon Fusion. More details at the end of the Instructable.
-I added old bike tires to the back wheels- see the last step.

Step 1: Gather Materials

Materials:
-Power Wheels $55 used (look around on Craig's List and eBay)
-Large servo $40
-2 Battery Holders $4
-FlySky transmitter and receiver $40
-screws (had)
-2 light switches (had)

Optional:
-Old Bike Tires (had)
-Krylon Fusion Spray Paint $4 at Walmart (get 3 cans)
-A piece of wood that will fit over the back (or you can keep the original seats, but with the wood makes it easier to get inside and troubleshoot the motors)
-hinges for the piece of wood

Making It Go Forwards/Backwards:
You have two options:
One is $12
The other is $125

The $12 option uses a small servo to pull the gas pedal that is already in the vehicle. Small servo $12. Revolt Lab has a guide on how to hook it up, make sure to plug the servo into Channel 2. Remember not to disconnect any wires if you do this, unless you want to move the battery to under the seat. Pros: a quick and cheap solution. Cons: pedal can get stuck, requiring you to go to the car and push it; the car can't go backwards from the remote; you have no speed control from the remote.

The $125 solution is a Sabertooth Motor Controller 2x25, which is what phwillys used. I am using this, and will post steps on this Instructable as soon as it comes in the mail. Pros: You can go very slowly all the way up to full speed in small increments; you can go backwards from the remote, and also control the speed for that very accurately; it is much more reliable. Cons: Obviously the price. If you make lots of remote controlled projects, this might be a good investment because you can switch it out between projects.

Total: $150, or $260.

Tools:
-Electric tape
-Hand saw
-Screwdriver (drill highly recommended)
-Scissors/wire cutters
-Soldering Iron (optional- I twist the wires together and cover with electrical tape)

Optional:
Netbook and computer (coming soon)

Step 2: Remove Parts From Power Wheels

First you need to remove all the unnecessary parts.

1. I had all ready removed the seats, windshield, and back bars years ago.

A piece of wood can go over the area where the seats were if you choose to.

2. Saw off the whole steering wheel except for the center circle.

3. Turn the Power Wheels over to access the pedal tabs. Press in all four tabs to remove the gas pedal. (there is a long bar going behind the pedal to hold the wires; remove this). Also saw off the excess plastic on the pedal.

Step 3: Move Parts and Attach Servos

Next you will need to move the battery and attach the servos.

1. Unscrew the screws holding the shifter to the Power Wheels. Pull the battery connector out of the battery (see pic). Cut the wires going from the battery connector to the vehicle.

2. Move the battery to the back of the vehicle, there is a space under the seat for it (moving the battery gives traction to the back tires and makes steering easier).

3. The wires that were just cut can be found under the dash. They go from the pedal to the shifter. Re-connect one wire to the battery connector. Screw the other one into one of the switches (you may need an extension wire). Get another wire and connect it from the switch to the wire that is still cut. Put the switch somewhere for easy access (the dashboard).

Attach Servo:

1. Make sure the + shaped pieces are on both the servos.

2. To attach the steering servo, use the included screws and screw it through the holes and into the edge of the steering wheel (see pic). Use two pieces of wood and screw them into the dash, making sure they align with the servo. Use two thick pieces of wire to secure them to the servo.

Step 4: Attach Servos to Receiver

Next attach the servo to the receiver in channel 1. Make sure to turn on the remote before attaching the battery pack to the power (make sure the +and- line up).

The Power Wheels should now be able to steer remote controlled!

If the servo moves the wrong way you can go to the remote product page to watch a video on how to reverse the direction.

You can attach the second switch to the servo battery to easily turn off the receiver.

I am going to find a plastic bin to cover over all the steering servo, and I am going to paint the whole thing black.

To make it a spy robot, put the netbook in the back with a webcam on the front of the vehicle and skype the bigger computer.

Comment with any ideas or corrections to make this instructable better!

Step 5: Paint Job

I decided to paint it black because I was tired of the red with flames.

-First I covered the Jeep and Wrangler logos with masking tape, which is optional.
-Then I unscrewed the tail lights and popped out the front grill and headlights. I painted the cover for the headlights and the tail light rim.
-I used Krylon Fusion, which bonds to plastic without priming. I ended up having to go out and get more paint and they were out of Krylon so I got Valspar Plastic Paint. I advise you dont use Valspar, it looks good with the krylon on the jeep, but it drips all over my hands and smells awful compared to the Krylon, which went on well with no fumes or dripping.
-I also painted a piece of wood for the back of the jeep, the tail light rims, head light covers, and grille.
-It took an hour to dry, but it says it takes a week to become chip-resistant.

Step 6: Tire Traction

-I added old bike tires to the back wheels for added traction. I did not put any on he front so the servo wouldn't have a hard time steering and because I ran out of tires.

Getting The Tires:
Find an old bike with deflated tires. Start by cutting across the tire of an old bike (make sure it is deflated). Then start cutting around the rim, leaving about 1/2" on the wheel (I found thick wire running through mine that was really hard to cut). The first tire I ended up cutting through the wire to get the whole thing off- then I had to cut off the area with the wire in it. I would recommend just cutting around it to save time, which is what I did on the second tire.

Attaching The Tires:
I attached them with a staple gun. You can try to screw it in with a drill, too.