Have never tried this myself, but here's Butterball's take on things: http://www.butterball.com.... This also seems like a good reference: http://www.yankeemagazine...

Cook's Illustrated has directions for both charcoal and gas grilled turkey, Nov/Dec 1999. Naturally, they have all the science behind both methods. We tried the charcoal one a few Thanksgivings ago and it was excellent. We grill turkey thighs often (especially excellent for traditional Mole Poblano). If you do not have a friend with a back stash of Cook's, you can subscribe to their internet service for a small fee for a couple of weeks & print out as much as you want. Worth it.

Good advice! I will update with results....

Good luck, and happy Thanksgiving!

The turkey turned out perfectly! I highly recommend this method. It gave us the ability to use the oven for other things. Also, the 15 lbs turkey cooked in under 2 hours. The only method is to watch the flame to make sure the temp is consistent-- but that wasn't too hard.