I copied this from another site, It was submitted from the wife of a New Zealand based Outfitter:
BASIC TECHNIQUE FOR BRINING A TURKEY:
Wash the bird, inside and out, in cool running water. Combine 2/3 to 1cup salt (or more, depending on recipe) with 1 gallon of water and stir until salt dissolves.
[Optionally, you may add 1/2 cup or so of sugar (white or brown) which will balance the saltiness, help with the browning, and aid the moisture-absorption of the brine, then bring the whole thing to a boil for 5 minutes to blend flavors - along with (as desired) cracked black pepper, a pinch of thyme, some cloves, allspice, bay leaves, peeled garlic cloves, crushed juniper berries - and/or other seasonings to your taste.]
Think about the stuffing to be used, if any, and other components of the meal when choosing seasonings to be added to the brine mixture.
The flavor the seasoning will impart to the turkey will be mild. If you make this flavored brine, heating it to combine flavors, be sure to allow it to cool before immersing the turkey.
Pour the brine over the turkey in a bucket or pot (plastic, stainless steel or enamel – not aluminum or other “reactive” metal) just large enough to hold both. If the turkey is completely covered with brine, discard any extra brine.
If it is not covered, make and add more brine as needed to immerse the bird, or top the bird with a heavy weight to keep it under the liquid. Cover the pot and refrigerate for 6 hours - or up to 24 hours, turning 2 or 3 times, making sure each time that the brine completely covers the turkey.
Remove the turkey from the brine, rinse, pat dry with paper towels, and roast as usual. Brining makes an exceptionally moist and juicy (but not watery) turkey.
Note: Some people just do not have enough room in the refrigerator to put the brining turkey in its pot. In that case, we have found that using an insulated cooler, placing the turkey and brine in a heavy plastic bag in the cooler, and surrounding the closed bag with blue ice or regular ice can work just fine.
IMPORTANT: Use a thermometer to be sure that the temperature of the brine never rises above 40 degrees – for safety’s sake!
Extra Step For Crispiest Skin: Remove the turkey from the brine, pat dry with paper towels, and return the turkey to the empty pot. Allow the turkey to stand, refrigerated, for 6 hours or overnight. This resting period has the added advantage of evening the degree of brininess throughout the meat (it will be less salty on the surface of the meat, more evenly brined throughout), and resting produces a slightly more tender result.
ULTIMATE BRINE FOR TURKEY
1 1/2 cups, Kosher salt**
**Note below regarding amount of salt
1 1/4 cups, brown sugar
10 whole cloves
3 tsp, black peppercorns
1 1/2 gallons (6 quarts) apple juice or cider (non-alcoholic)
the peel from one orange or one tangerine (colored part only - not white pith)
[optional: 3 teaspoons, dried thyme and/or 3 teaspoons, dried sage]
Combine all ingredients in a non-reactive pot, bring mixture to a boil, lower heat and simmer for 15-20 minutes (partly covered). Allow brine to cool completely.
Rinse turkey under cool running water, inside and out (remove giblets from body cavity). Pat turkey dry with paper towels, then immerse turkey in cooled brine.* Turkey should be completely submerged in liquid (place a plate on top of the bird if necessary to keep it covered with the liquid).
Cover the pot and refrigerate for 8-10 hours or up to 24 hours. Remove turkey, rinse, pat dry, and roast as usual. [See note under “basic technique” for extra step to get crispiest skin.]
*Be sure the container used for brining turkey is non-reactive: use enamel, glass or crockery or stainless steel - never cast iron or aluminum. The pot should be just large enough to contain the turkey (so the brine will be sufficient to cover the bird).
** NOTE REGARDING THE AMOUNT OF SALT IN BRINE:
A milder brine may be made, which may have a less flavorful result – but if salt is a concern (the entire turkey will absorb only 10-15% of the brine) the amount of salt may be reduced. For the desired chemical effect to take place, however, the proportions cannot be less than 2/3 to 1 cup of salt per gallon (4 quarts) of water.