I usually brine it at least for 12 hours. My DH makes wine so we always have large buckets that the juice comes in, so I use one of these for my Turkeys which are usually no more than 14 pounds.
We also have an extra fridge so I use that to keep it cool and at Christmas it's usually cold enought to put it in the garage. Make sure you have a tight lid on it though. I guess that doesn't help if you live in LA though.
When I roast it in the oven I use the same method as Hysmith.
For Thanksgiving this year (Canada is in October) I did my Turkey on the BBQ after brining. I did try somehing different this time though. In the summer we always BBQ whole chickens sitting on 1/2 full beer cans. I decided to try it with the turkey. I got a 1 lb coffee can, filled it up half way with beer, then sat the turkey over it. UMMMMMMM it was soooo good. Very juicy and tender.