Welcome to the board.
I'm in the process of building my PID using the plans on the recipe site (click on the smoker in my signature for the recipe site, then under Bradley Accessories or something like that, the link to the PID instructions).
It looks to be written well enough that I can follow it, but make sure on the wiring diagram, you read it from right to left. Also, the thermocouple in the parts list is from Auber, many here recommend using an Omega instead. Omega has a website, or they are available on ebay most of the time from a user with the screen name of "kulast" or something close to that. I picked up a pair of them with 8 foot leads, 6 inch stainless probe 3/16 diameter, for about $17.50 plus shipping.
One more thing, it's not in the original plans, but a lot of people put a pair of fuses in there too. One on the main input wire that is 10 Amps, and another on the hot going into the PID controller that is 1 Amp.
I hope I've helped.