All you need is the RockBand 1 (I haven't tried with the RockBand 2 drums yet) drums, a screwdriver, and possibly the knowledge of how to make a simple splice.
Here is a video of me playing with them (for the first time)
Step 1: Dismantling the Drum Set
-Next you need to unscrew all the screws on the backside of the RockBand drums, and basically every screw you think will help take it apart
-After you have taken all the screws out, if the plastic pieces don't separate easily, there are also some screws under the foam inside of the middle 2 drum
You should be able to take the yellow and blue wires out, but the green and red should be stuck in between some plastic
Step 2: The Wires
-One control circuit
-4 colored wires with sensors on the end
-1 input for the bass pedal
-1 USB wire
Step 3: Attaching to the Real Drum Set
Step 4: The Bass Pedal
UPDATE: After I published this instructable, I saw a good instructable on making the bass pedal work, you can view it here.
My idea is that you can place the piece next to (or in between for double bass) the batter head and tape/glue a magnet on side of the batter head(s). my other idea is keep the trigger under the pedal and a magnet on the underside of the pedal. I haven't tried either of those ideas, nor do I plan on trying them, but I thought I would put them out there incase anyone wanted to try them, and if you do, please leave a comment and tell my how it went!
Step 5: Play!
YOU WILL DEFINITELY WANT TO RECALIBRATE YOUR DRUM SET IN THE SETTINGS.
If your TV has a headphone port, or you can somehow get the sound into headphones would definitely be ideal. There are plenty of guides on how to do that, but I still havn't yet so I'll leave that up to you, but its still fun either way. One problem I have had is that some times I'd hit blue and it would shake the whole bass drum and activate yellow too, and since the floor tom is so large, it sometimes triggers green twice. Also, be careful not to hit the sensors, it might be a good idea to use the foam from inside the RB drums to protect the sensors. Have fun playing with your new RockBand drum set!