I smoked several turkeys for the first time last year. They were the tastiest turkey I've ever had. When I was carving them, I had to put the cutting board in a raised lip baking sheet because they were SO juicy!
I brined them for 2 to 3 days in an ice chest. The brine recipe I used was a combination of several that I got on the internet, maybe even from here on HT.
Handful of sage
Handful of thyme
Several bay leaves
Freshly cracked peppercorns (put them in a ZipLock bag and give them a few whacks with a rubber mallet)
4 oranges, zested, sliced in half, and juiced (toss the juiced fruit in as well)
4 lemons, zested, sliced in half, and juiced (toss the juiced fruit in as well)
2 cups salt
1 cup sugar
Dissolve the sugar and salt in a couple of quarts of boiling water and let cool. Place all the ingredients and defrosted turkey in a cooler and cover with a bag of ice. Add enough cold water to cover the turkey. After the first day, check every 12 hours or so to see if you need to add more ice to keep chilled. When you pull it out of the brine, rinse well and pat dry with paper towels, inside and out.
Rub the turkey with vegetable oil and season liberally with your favorite poultry rub under the skin (lift it up and rub it in well) and outside. I used this:
http://www.oakridgebbq.com/shop/game-bird-n-chicken/#axzz3Jf7nVnnT
Place a temp probe in the meatiest part of the thigh, being sure not to touch bone, and another temp probe in the meatiest part of the breast.
Place in your smoker (I used a Weber Smoky Mountain) and smoke at 250 to 300 degrees until it's almost done. I used apple wood. I pull it off when it's 5 to 10 degrees under the recommended temperature, and rest it for 30 to 60 minutes. The temp will continue to rise during the resting period. You can either foil it, or I use the same cooler that I used to brine the turkey after having washed it thoroughly, bleached it, and rinsed well.
The turkey skin will be MUCH darker than a roasted turkey. The meat will have a pink color, especially at the edges. The color is not because it is underdone, but is due to the smoking process.
YUM!
BTW, through trial and error, I have found that smaller turkeys tend to be juicier than larger ones, probably because the brine penetrates deeper. So I think if you're feeding a large crowd, buy smaller turkeys but smoke more of them.