Any wood (except maybe mesquite) is a good choice for your smoke. I like a mixture of hickory and cherry. This gives a strong smoke flavor from the hickory and a sweet flavor from the cherry wood. Of course, whatever you like is the way to go.
If using large wood chunks, you don't need to soak the wood. However, if you are using smaller wood chips, I would recommend soaking them first. This slows down the burn rate and gives a longer, more consistent smoke. Make sure you shake off as much water as possible. Wood chips should be damp but not dripping.
Once the wood is placed into the smoker, close it up and watch the temperature. Unless you need to rotate the turkey during the cooking time there isn't any reason to open the smoker for several hours. Keeping the smoker closed holds in the heat and the smoke, so don't waste it by opening the smoker excessively.