Step 1: Assemble Materials
One Android Device - Mine is a Mach Speed Trio 4.3" Mini Internet Tablet. Any Android device that has USB Host mode will do though.
One PS3 Controller - Mine is a generic ProEX I found at Walmart for $20 last year. Others may work. This was used because it's what I had on hand and it worked by just plugging it in. If you have a controller that you just HAVE to use but it's not plug and play, Google is your friend and you may be able to track down the appropriate drivers.
One Universal car dock - Any will do. What you choose will determine how you attach yours. I recommend trying to find something with a smaller suction cup as you then may be able to use it to just attach to the back of your controller and forgo the rubberbands all together.
Rubberbands - My suction cup is too large for the back of the controller so this is what I had to do to attach it all together.