Brake controller

I did a search and did not find exactly what I was looking for. I did see some information about a brake controller but my question is what additional wiring\equipment needs to be purchased to get the brakes on the trailer to work. I have the trailer hitch installed with the new wiring harness you have to buy for the 05's. Do I now ONLY need the brake controller and it will integrate into the new system or do I need more stuff to make it work? I am plannig to tow a car across the country, over mountains and feel I'll really need the trailer brakes.

I have a brake controller installed in my 05. I ordered the Nissan harness for 8 dollars and wired it to my drawtight brake controller. I made a little insert that slips into the front wallet and phone tray and it holds it tight and I can remove it quickly when not needed. I have the factory hitch installed so it has the wiring to the harness in the back. No problems.