Here are a couple sites that you may want to look at for the turkey and brining.
The virtual weber bullet has a lot of useful info whether or not you are using a WSM.
http://www.virtualweberbullet.com/turkey3.html
I use Alton Brown's brine recipe, but I vary it a little in that I use apple juice rather than orange juice and add rosemary sprigs. I smoke poultry with apple wood and maybe some pecan.
Alton Brown Orange Juice Brine
1 qt vegetable stock, chilled (regular, not low sodium - that's important)
1/2 cup kosher salt
1/4 cup dark brown sugar
1 tsp black peppercorns (I usually use more like 1 tbsp, but I like pepper)
2 bay leaves
1 qt. orange juice, chilled
2 qts. ice water
Bring 2 cups of the stock, the salt, brown sugar, peppercorns, and bay leaves to a boil. Dissolve the sugar and salt, and cut the fire. Add in the remaining stock, orange juice, and ice water. Once the brine has cooled to 40F or under, add the meat and keep in a cold place (under 40F). Brine for 8-48 hours.
Here is another if AB's brine recipes. I may try this this year
http://www.foodnetwork.com/recipes/alton-brown/good-eats-roast-turkey-recipe/index.html
I always stuff the cavity with rosemary, thyme, sage, apple, onion.
Do a practice run on a breast sometime prior to the big day.
